s390/zcrypt: Improve CCA CPRB length and overflow checks
CVE-2026-80546 · published 26 Aug 2026
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-80546?
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Who is affected
- Linux Linux: 20b0b0159390fa5c00a435195649680fefda81e0 to < 584400144020f40365de3972c4763da520e7280e, e2c6d91eb8b1533753755f07803e47eceed263d0 to < 50fe5133dcb46449daf2435fa705264364411129, e2c6d91eb8b1533753755f07803e47eceed263d0 to < 35ac6754ba6da45fd193f5ce3f665f7490b830d5, f9da85d4780515f65983e0af151458599adaef3d
- Linux Linux: 7.1
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
s390/zcrypt: Improve CCA CPRB length and overflow checks
The xcrb_msg_to_type6cprb_msgx() function lacks proper input
validation, creating security vulnerabilities:
1. Integer overflow after CEIL4 alignment: Signed int variables could
overflow during 4-byte boundary alignment, causing undersized
buffer allocations or incorrect bounds checking.
2. Missing minimum size validation: The CPRBX structure is copied from
userspace without verifying sufficient buffer length. Undersized
buffers cause uninitialized memory access when reading structure
fields like cprbx.cprb_len and cprbx.domain.
3. Arithmetic overflow in sum calculations: Adding control block and
data block sizes could overflow, bypassing size checks and enabling
buffer overflows.
Fix by using size_t for length calculations, adding U32_MAX boundary
checks after alignment, validating minimum control block size before
copying from userspace, and detecting sum calculation overflows.
Check your whole app
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References
- git.kernel.org/stable/c/584400144020f40365de3972c4763da520e7280e
- git.kernel.org/stable/c/50fe5133dcb46449daf2435fa705264364411129
- git.kernel.org/stable/c/35ac6754ba6da45fd193f5ce3f665f7490b830d5
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON