s390/zcrypt: Improve EP11 CPRB length and overflow checks
CVE-2026-80545 · 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-2026-80545?
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Who is affected
- Linux Linux: 20b0b0159390fa5c00a435195649680fefda81e0 to < f463f474773aa49ed1d6087d95d44cea7099fdc7, e2c6d91eb8b1533753755f07803e47eceed263d0 to < 2976b9d2e716c7e5487ca7c29a7bd076cf9adf08, e2c6d91eb8b1533753755f07803e47eceed263d0 to < 17ac0bc866fc624cd05f022dcd8b730c0af11bb1, 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 EP11 CPRB length and overflow checks
The xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input
validation, creating security vulnerabilities:
1. Missing minimum size validation: The ep11_cprb structure and
subsequent payload fields (pld_tag, pld_lenfmt) are copied from
userspace without verifying sufficient buffer length.
2. Arithmetic overflow in length calculations: CEIL4 alignment could
overflow, bypassing size checks and enabling buffer overflows.
3. The payload is asn1 encoded but the function just uses a simple c
struct overlay to access some fields of the payload.
Fix by using size_t for length calculations, adding U32_MAX boundary
checks after alignment, and validating minimum request size and
minimum reply size before copying from userspace. Do a very simple
asn1 parsing of the payload up to the function value field.
Check your whole app
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References
- git.kernel.org/stable/c/f463f474773aa49ed1d6087d95d44cea7099fdc7
- git.kernel.org/stable/c/2976b9d2e716c7e5487ca7c29a7bd076cf9adf08
- git.kernel.org/stable/c/17ac0bc866fc624cd05f022dcd8b730c0af11bb1
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON