net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.15.160 to before 5.15.203; 6.1.84 to before 6.1.169; 6.6.18 to before 6.6.135; 6.7.6 to before 6.8 | 5.15.203, 6.1.169, 6.6.135, 6.8 | Patch available | CNA |
| Linux | Linux | 6.8 and later | 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23, 6.19.13, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 5.15.160 to before 5.15.203; 6.1.84 to before 6.1.169; 6.6.18 to before 6.6.135; 6.7.6 to before 6.8 Fixed in 5.15.203, 6.1.169, 6.6.135, 6.8 Patch available CNA
- Linux VendorLinux Affected 6.8 and later Fixed in 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23, 6.19.13, 7.0 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.15.160 to before 5.15.203; 6.1.84 to before 6.1.169; 6.6.18 to before 6.6.135; 6.7.6 to before 6.8; 6.8.1 to before 6.12.82; 6.13 to before 6.18.23; 6.19 to before 6.19.13 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* | 7.0 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* | 7.0 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* | 7.0 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* | 7.0 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* | 7.0 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* | 7.0 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* | 7.0 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.15.160 to before 5.15.203; 6.1.84 to before 6.1.169; 6.6.18 to before 6.6.135; 6.7.6 to before 6.8; 6.8.1 to before 6.12.82; 6.13 to before 6.18.23; 6.19 to before 6.19.13 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* Versions 7.0 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* Versions 7.0 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* Versions 7.0 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* Versions 7.0 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* Versions 7.0 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* Versions 7.0 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* Versions 7.0 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.15.203, 6.1.169, 6.6.135, 6.8
- Fix · CNA Linux (Linux) Fixed in 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23, 6.19.13, 7.0
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-31533
- 2026-10-03 Alias added: GHSA-r7wv-m72q-8qj8
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-25 EPSS moved to the below the 50th percentile
References
Patch 7
- https://git.kernel.org/stable/c/414fc5e5a5aff776c150f1b86770e0a25a35df3a
- https://git.kernel.org/stable/c/02f3ecadb23558bbe068e6504118f1b712d4ece0
- https://git.kernel.org/stable/c/0e43e0a3c94044acc74b8e0927c27972eb5a59e8
- https://git.kernel.org/stable/c/aa9facde6c5005205874c37db3fd25799d741baf
- https://git.kernel.org/stable/c/5d70eb25b41e9b010828cd12818b06a0c3b04412
- https://git.kernel.org/stable/c/2694d408b0e595024e0fc1d64ff9db0358580f74
- https://git.kernel.org/stable/c/a9b8b18364fffce4c451e6f6fd218fa4ab646705
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- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-31533 · CVE Program
- CVE-2026-31533 · NVD
- FIRST EPSS
- GHSA-r7wv-m72q-8qj8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-31533 · Red Hat security data · CC BY 4.0
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