# CVE-2025-39758: RDMA/siw: Fix the sendmsg byte count in siw_tcp_sendpages CVE-2025-39758 is fixed in 24 products on 1 platform, first by DEBIAN-CVE-2025-39758, released September 11, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-39758 - Priority: Routine - CVSS: 5.5 (Moderate) - EPSS: 0.0042 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 11, 2025 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39758 ## Description In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Fix the sendmsg byte count in siw_tcp_sendpages Ever since commit c2ff29e99a76 ("siw: Inline do_tcp_sendpages()"), we have been doing this: static int siw_tcp_sendpages(struct socket *s, struct page **page, int offset, size_t size) [...] /* Calculate the number of bytes we need to push, for this page * specifically */ size_t bytes = min_t(size_t, PAGE_SIZE - offset, size); /* If we can't splice it, then copy it in, as normal */ if (!sendpage_ok(page[i])) msg.msg_flags &= ~MSG_SPLICE_PAGES; /* Set the bvec pointing to the page, with len $bytes */ bvec_set_page(&bvec, page[i], bytes, offset); /* Set the iter to $size, aka the size of the whole sendpages (!!!) */ iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size); try_page_again: lock_sock(sk); /* Sendmsg with $size size (!!!) */ rv = tcp_sendmsg_locked(sk, &msg, size); This means we've been sending oversized iov_iters and tcp_sendmsg calls for a while. This has a been a benign bug because sendpage_ok() always returned true. With the recent slab allocator changes being slowly introduced into next (that disallow sendpage on large kmalloc allocations), we have recently hit out-of-bounds crashes, due to slight differences in iov_iter behavior between the MSG_SPLICE_PAGES and "regular" copy paths: (MSG_SPLICE_PAGES) skb_splice_from_iter iov_iter_extract_pages iov_iter_extract_bvec_pages uses i->nr_segs to correctly stop in its tracks before OoB'ing everywhere skb_splice_from_iter gets a "short" read (!MSG_SPLICE_PAGES) skb_copy_to_page_nocache copy=iov_iter_count [...] copy_from_iter /* this doesn't help */ if (unlikely(iter->count < len)) len = iter->count; iterate_bvec ... and we run off the bvecs Fix this by properly setting the iov_iter's byte count, plus sending the correct byte count to tcp_sendmsg_locked. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-64kb opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-64kb sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-debug opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-default sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-default-base opensuse-leap 15.6 | 6.4.0-150600.23.73.1.150600.12.32.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.6.1.160000.2.4 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-default-base sles 15.6 | 6.4.0-150600.23.73.1.150600.12.32.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.22.1.150700.17.15.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.6.1.160000.2.4 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-docs opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-docs sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-kvmsmall opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-livepatch-SLE15-SP6-RT_Update_16 sles 15.6 | 1-150600.1.3.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-livepatch-SLE15-SP6_Update_16 sles 15.6 | 1-150600.13.3.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_6 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2025:4141-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4141-1.md) | Nov 19, 2025 | | Linux | kernel-livepatch-SLE15-SP7_Update_6 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-obs-build opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-obs-build sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-obs-qa opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-rt_debug opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-source opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-source sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-source-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-source-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-source-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-source-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-syms opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-syms sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | kernel-syms-azure opensuse-leap 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-syms-azure sles 15.6 | 6.4.0-150600.8.52.1 | [SUSE-SU-2025:03634-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03634-1.md) | Oct 17, 2025 | | Linux | kernel-syms-azure sles 15.7 | 6.4.0-150700.20.18.1 | [SUSE-SU-2025:4132-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4132-1.md) | Nov 18, 2025 | | Linux | kernel-syms-rt opensuse-leap 15.6 | 6.4.0-150600.10.55.1 | [SUSE-SU-2025:3751-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3751-1.md) | Oct 23, 2025 | | Linux | kernel-zfcpdump opensuse-leap 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.6.1 | [OPENSUSE-SU-2025:20081-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20081-1.md) | Nov 25, 2025 | | Linux | kernel-zfcpdump sles 15.6 | 6.4.0-150600.23.73.1 | [SUSE-SU-2025:03600-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-03600-1.md) | Oct 15, 2025 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.22.1 | [SUSE-SU-2025:4057-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-4057-1.md) | Nov 11, 2025 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.6.1 | [SUSE-SU-2025:21139-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21139-1.md) | Nov 25, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.43-1 | [DEBIAN-CVE-2025-39758](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39758.md) | Sep 11, 2025 | | Linux | linux Debian 14 | 6.16.3-1 | [DEBIAN-CVE-2025-39758](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39758.md) | Sep 11, 2025 | --- Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.