Libssh: write beyond bounds in binary to base64 conversion functions
CVE-2025-4877 is fixed in 5 products on 1 platform, first by libssh-4 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4, released June 24, 2025. It is not reported as exploited. Patch Radar priority: Routine.
There's a vulnerability in the libssh package where when a libssh consumerpasses in an unexpectedly large input buffer to ssh_get_fingerprint_hash()function. In such cases the bin_to_base64() function can experience aninteger overflow leading to a memory under allocation, when that happensit's possible that the program perform out of bounds write leading to aheap corruption.This issue affects only 32-bits builds of libssh.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| libssh · Debian 11.6 (bullseye) | 0.9.8-0+deb11u2 | DLA-4385-1 | Nov 27, 2025 |
| libssh · Debian 12.15 (bookworm) | 0.10.6-0+deb12u2 | DEBIAN-CVE-2025-4877 | Aug 20, 2025 |
| libssh · Debian 13.5 (trixie) | 0.11.2-1 | DEBIAN-CVE-2025-4877 | Aug 20, 2025 |
| libssh · Debian 14 | 0.11.2-1 | DEBIAN-CVE-2025-4877 | Aug 20, 2025 |
| libssh · RHEL 9 | 0:0.10.4-18.el9 | RHSA-2026:18683 | May 27, 2026 |
| libssh · almalinux 9 | 0.10.4-18.el9 | ALSA-2026:18683 | May 19, 2026 |
| libssh · ol 9 | 0:0.10.4-18.el9 | ELSA-2026-18683 | Jun 12, 2026 |
| libssh · opensuse-leap 15.6 | 0.9.8-150600.11.3.1 | SUSE-SU-2025:02229-1 | Jul 4, 2025 |
| libssh · rocky 9 | 0:0.10.4-18.el9 | RLSA-2026:18683 | May 28, 2026 |
| libssh · sles 15.6 | 0.9.8-150600.11.3.1 | SUSE-SU-2025:02229-1 | Jul 4, 2025 |
| libssh · sles 15.7 | 0.9.8-150600.11.3.1 | SUSE-SU-2025:02229-1 | Jul 4, 2025 |
| libssh-4 · Ubuntu 18.04.6 LTS (bionic) | 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4 | libssh-4 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4 | Jun 24, 2025 |
| libssh-4 · Ubuntu 20.04 LTS (focal) | 0.9.3-2ubuntu2.5+esm1 | libssh-4 0.9.3-2ubuntu2.5+esm1 | Jun 24, 2025 |
| libssh-4 · Ubuntu 22.04.1 LTS (jammy) | 0.9.6-2ubuntu0.22.04.4 | libssh-4 0.9.6-2ubuntu0.22.04.4 | Jun 24, 2025 |
| libssh-4 · Ubuntu 24.04.5 LTS (noble) | 0.10.6-2ubuntu0.1 | libssh-4 0.10.6-2ubuntu0.1 | Jun 24, 2025 |
| libssh-4 · Ubuntu 24.10 (oracular) | 0.10.6-3ubuntu1.1 | libssh-4 0.10.6-3ubuntu1.1 | Jun 25, 2025 |
| libssh-4 · Ubuntu 25.04 (plucky) | 0.11.1-1ubuntu0.1 | libssh-4 0.11.1-1ubuntu0.1 | Jun 25, 2025 |
| libssh-config · RHEL 9 | 0:0.10.4-18.el9 | RHSA-2026:18683 | May 27, 2026 |
| libssh-config · almalinux 9 | 0.10.4-18.el9 | ALSA-2026:18683 | May 19, 2026 |
| libssh-config · ol 9 | 0:0.10.4-18.el9 | ELSA-2026-18683 | Jun 12, 2026 |
| libssh-devel · RHEL 9 | 0:0.10.4-18.el9 | RHSA-2026:18683 | May 27, 2026 |
| libssh-devel · almalinux 9 | 0.10.4-18.el9 | ALSA-2026:18683 | May 19, 2026 |
| libssh-devel · ol 9 | 0:0.10.4-18.el9 | ELSA-2026-18683 | Jun 12, 2026 |
| libssh-gcrypt-4 · Ubuntu 18.04.6 LTS (bionic) | 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4 | libssh-gcrypt-4 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4 | Jun 24, 2025 |
| libssh-gcrypt-4 · Ubuntu 20.04 LTS (focal) | 0.9.3-2ubuntu2.5+esm1 | libssh-gcrypt-4 0.9.3-2ubuntu2.5+esm1 | Jun 24, 2025 |
| libssh-gcrypt-4 · Ubuntu 22.04.1 LTS (jammy) | 0.9.6-2ubuntu0.22.04.4 | libssh-gcrypt-4 0.9.6-2ubuntu0.22.04.4 | Jun 24, 2025 |
| libssh-gcrypt-4 · Ubuntu 24.04.5 LTS (noble) | 0.10.6-2ubuntu0.1 | libssh-gcrypt-4 0.10.6-2ubuntu0.1 | Jun 24, 2025 |
| libssh-gcrypt-4 · Ubuntu 24.10 (oracular) | 0.10.6-3ubuntu1.1 | libssh-gcrypt-4 0.10.6-3ubuntu1.1 | Jun 25, 2025 |
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