CVE-2026-63805

Local kernel crash via NX context type confusion

Published Jul 19, 2026 · Updated Jul 19, 2026

Type confusion in Linux Kernel 5.5 through 6.18.37 and 6.19 through 7.1.2 allows local users to crash the kernel via AF_ALG. nx_crypto_ctx_shash_exit and nx_crypto_ctx_skcipher_exit pass an nx_crypto_ctx pointer to nx_crypto_ctx_exit, which wrongly treats it as a crypto_tfm pointer and derives an invalid context address before freeing memory. A normal local account can trigger the fault when AF_ALG selects the NX driver on an IBM Power pSeries system, causing a kernel oops and service interruption.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Linux Kernel 5.5 through 6.18.37 and 6.19 through 7.1.2 allows local users to crash the kernel via AF_ALG. nx_crypto_ctx_shash_exit and nx_crypto_ctx_skcipher_exit pass an nx_crypto_ctx pointer to nx_crypto_ctx_exit, which wrongly treats it as a crypto_tfm pointer and derives an invalid context address before freeing memory. A normal local account can trigger the fault when AF_ALG selects the NX driver on an IBM Power pSeries system, causing a kernel oops and service interruption.

The record

CVE
CVE-2026-63805
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.5
  2. Affected versionversion=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <4e67f504ee9ded15e256b64f4fde150e917381d7
  3. Affected versionversion=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <833033e6e55acf11304ff7bbbdf18351d139c281
  4. Affected versionversion=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <8d8507a457667f23477a15496b91908a5b5b7cf3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.5; version=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <4e67f504ee9ded15e256b64f4fde150e917381d7; version=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <833033e6e55acf11304ff7bbbdf18351d139c281; version=bfd9efddf990d152dc9912fdca520c5e1e19e1e2 <8d8507a457667f23477a15496b91908a5b5b7cf3

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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