CVE-2026-31533net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption The -EBUSY handling in tls_do_encryption(), introduced by commit 859054147318 ("net: tls: handle backlogging of crypto requests"), has a use-after-free due to double cleanup of encrypt_pending and the scatterlist entry. When crypto_aead_encrypt() returns -EBUSY, the request is enqueued to the cryptd backlog and the async callback tls_encrypt_done() will be invoked upon completion. That callback unconditionally restores the scatterlist entry (sge->offset, sge->length) and decrements ctx->encrypt_pending. However, if tls_encrypt_async_wait() returns an error, the synchronous error path in tls_do_encryption() performs the same cleanup again, double-decrementing encrypt_pending and double-restoring the scatterlist. The double-decrement corrupts the encrypt_pending sentinel (initialized to 1), making tls_encrypt_async_wait() permanently skip the wait for pending async callbacks. A subsequent sendmsg can then free the tls_rec via bpf_exec_tx_verdict() while a cryptd callback is still pending, resulting in a use-after-free when the callback fires on the freed record. Fix this by skipping the synchronous cleanup when the -EBUSY async wait returns an error, since the callback has already handled encrypt_pending and sge restoration.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 3ade391adc584f17b5570fd205de3ad029090368 before 414fc5e5a5aff776c150f1b86770e0a25a35df3a; from cd1bbca03f3c1d845ce274c0d0a66de8e5929f72 before 02f3ecadb23558bbe068e6504118f1b712d4ece0; 13eca403876bbea3716e82cdfe6f1e6febb38754 builds before 0e43e0a3c94044acc74b8e0927c27972eb5a59e8; from 8590541473188741055d27b955db0777569438e3 before aa9facde6c5005205874c37db3fd25799d741baf; 8590541473188741055d27b955db0777569438e3 builds before 5d70eb25b41e9b010828cd12818b06a0c3b04412; 8590541473188741055d27b955db0777569438e3 builds before 2694d408b0e595024e0fc1d64ff9db0358580f74; from 8590541473188741055d27b955db0777569438e3 before a9b8b18364fffce4c451e6f6fd218fa4ab646705; ab6397f072e5097f267abf5cb08a8004e6b17694; and 4 more ranges | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.15.160 before 5.15.203; from 6.1.84 before 6.1.169; from 6.6.18 before 6.6.135; from 6.7.6 before 6.8; from 6.8.1 before 6.12.82; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 7.0; and 6 more ranges | NVD |
References
- https://git.kernel.org/stable/c/414fc5e5a5aff776c150f1b86770e0a25a35df3apatch
- https://git.kernel.org/stable/c/02f3ecadb23558bbe068e6504118f1b712d4ece0patch
- https://git.kernel.org/stable/c/0e43e0a3c94044acc74b8e0927c27972eb5a59e8patch
- https://git.kernel.org/stable/c/aa9facde6c5005205874c37db3fd25799d741bafpatch
- https://git.kernel.org/stable/c/5d70eb25b41e9b010828cd12818b06a0c3b04412patch
- https://git.kernel.org/stable/c/2694d408b0e595024e0fc1d64ff9db0358580f74patch
- https://git.kernel.org/stable/c/a9b8b18364fffce4c451e6f6fd218fa4ab646705patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.