# CVE-2021-47496: linux: In the Linux kernel, the following vulnerability has been resolved:  net/tls: Fix flipped sign in tls_err_abort() cal...

CVE-2021-47496 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47496, released May 22, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47496
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0048
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 22, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  net/tls: Fix flipped sign in tls_err_abort() calls  sk->sk_err appears to expect a positive value, a convention that ktls doesn't always follow and that leads to memory corruption in other code. For instance,      [kworker]     tls_encrypt_done(..., err=<negative error from crypto request>)       tls_err_abort(.., err)         sk->sk_err = err;      [task]     splice_from_pipe_feed       ...         tls_sw_do_sendpage           if (sk->sk_err) {             ret = -sk->sk_err;  // ret is positive      splice_from_pipe_feed (continued)       ret = actor(...)  // ret is still positive and interpreted as bytes                         // written, resulting in underflow of buf->len and                         // sd->len, leading to huge buf->offset and bogus                         // addresses computed in later calls to actor()  Fix all tls_err_abort() callers to pass a negative error code consistently and centralize the error-prone sign flip there, throwing in a warning to catch future misuse and uninlining the function so it really does only warn once.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.3-1 | [DEBIAN-CVE-2021-47496](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47496.md) | May 22, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.3-1 | [DEBIAN-CVE-2021-47496](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47496.md) | May 22, 2024 |
| Linux | linux Debian 14 | 5.15.3-1 | [DEBIAN-CVE-2021-47496](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47496.md) | May 22, 2024 |

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