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CVE-2026-63805

HIGH 7.8

Published 2026-07-19 · Last modified 2026-07-20

In the Linux kernel, the following vulnerability has been resolved: crypto: nx - fix nx_crypto_ctx_exit argument nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...) but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *. Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx call. This fixes the following oops: BUG: Unable to handle kernel data access at 0xc0403effffffffc8 Faulting instruction address: 0xc000000000396cb4 Oops: Kernel access of bad area, sig: 11 [#15] Call Trace: nx_crypto_ctx_shash_exit+0x24/0x60 crypto_shash_exit_tfm+0x28/0x40 crypto_destroy_tfm+0x98/0x140 crypto_exit_ahash_using_shash+0x20/0x40 crypto_destroy_tfm+0x98/0x140 hash_release+0x1c/0x30 alg_sock_destruct+0x38/0x60 __sk_destruct+0x48/0x2b0 af_alg_release+0x58/0xb0 __sock_release+0x68/0x150 sock_close+0x20/0x40 __fput+0x110/0x3a0 sys_close+0x48/0xa0 system_call_exception+0x140/0x2d0 system_call_common+0xf4/0x258 .. which came from hardlink(1) opportunistically using AF_ALG. The same problem exists with nx_crypto_ctx_skcipher_exit getting a context it wasn't expecting, but apparently nobody hit that for years.

ELEVATED IMPACT

Severe if exploited (CVSS 7.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.1%chance of exploitation in 30 days · 3rd percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

7.8CVSS 3.1 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Requires local access to the host
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-63805/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-63805/poc.json

Affected

Vendors Linux

Products Linux

Weakness (CWE)

Not classified.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

All CVSS metrics

  • HIGH 7.8 v3.1 · CNA Primary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • HIGH 7.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Technical & other

Sources: NVD · CVE.org · EPSS