CVE-2026-68453: Linux kernel · s390/zcrypt: Fix buffer over-read in cca_cipher2protkey
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| 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
- git.kernel.org/stable/c/d0951ed366710a1a303b7cb2f8eb3d866cd68fc6 (opens in a new tab)
- git.kernel.org/stable/c/353e442d18084b24fb3ede4e5adfca26b25f0e89 (opens in a new tab)
- git.kernel.org/stable/c/a57fd7fcdb63e2d5ceac78bbe825ec986062a9da (opens in a new tab)
- git.kernel.org/stable/c/3b2abee2a678607ae27975bc6833785c2002df43 (opens in a new tab)
- git.kernel.org/stable/c/36b230835b8a008266aad22168ca52afacc8a58d (opens in a new tab)