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VulnerabilityPublished Updated

CVE-2026-68453: Linux kernel · s390/zcrypt: Fix buffer over-read in cca_cipher2protkey

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in d0951ed366710a1a303b7cb2f8eb3d866cd68fc6 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in d0951ed366710a1a303b7cb2f8eb3d866cd68fc6, a57fd7fcdb63e2d5ceac78bbe825ec986062a9da, 353e442d18084b24fb3ede4e5adfca26b25f0e89 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 4bc123b18ce6ae6c42c69d0456b5acbd2f7bc8bd, < d0951ed366710a1a303b7cb2f8eb3d866cd68fc6
Fixed in
  • d0951ed366710a1a303b7cb2f8eb3d866cd68fc6
LinuxLinuxAffected
  • ≥ 4bc123b18ce6ae6c42c69d0456b5acbd2f7bc8bd, < a57fd7fcdb63e2d5ceac78bbe825ec986062a9da
Fixed in
  • a57fd7fcdb63e2d5ceac78bbe825ec986062a9da
LinuxLinuxAffected
  • ≥ 4bc123b18ce6ae6c42c69d0456b5acbd2f7bc8bd, < 353e442d18084b24fb3ede4e5adfca26b25f0e89
Fixed in
  • 353e442d18084b24fb3ede4e5adfca26b25f0e89
LinuxLinuxAffected
  • ≥ 4bc123b18ce6ae6c42c69d0456b5acbd2f7bc8bd, < 36b230835b8a008266aad22168ca52afacc8a58d
Fixed in
  • 36b230835b8a008266aad22168ca52afacc8a58d
LinuxLinuxAffected
  • ≥ 4bc123b18ce6ae6c42c69d0456b5acbd2f7bc8bd, < 3b2abee2a678607ae27975bc6833785c2002df43
Fixed in
  • 3b2abee2a678607ae27975bc6833785c2002df43
LinuxLinuxAffected
  • =5.4
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Fix buffer over-read in cca_cipher2protkey Add validation of both the actual key buffer size and token length fields in all the cca_check_sec*token() functions. Additionally check in cca_gencipherkey() for possible underflow with returned key size. The CCA token structures contain user-controlled len fields that were used in operations without proper validation against both the actual buffer size and minimum token structure size. An attacker could set this field larger than the actual buffer size, leading to reading beyond buffer boundaries. This may result in a kernel crash or exposure of memory via sending this as part of a request down to the crypto card. Also an attacker could have used a very small len value and thus enforce a buffer under-run which may produce similar effects as a over-read. So now a key must - key buf length must be at least sizeof the token struct - the key len field inside the token must fit into the range of sizeof key token struct ... key buf length

References

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