# CVE-2026-74671: ima: fix out-of-bounds read in xattr_verify()

> A local attacker can trigger an out-of-bounds read in the Linux kernel's IMA subsystem via a truncated extended attribute, potentially leaking memory or causing a crash.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 22 Aug 2026
- **Also known as:** AZL-97203, BELL-CVE-2026-74671, DEBIAN-CVE-2026-74671, GHSA-g8m3-q9h2-qp8g, UBUNTU-CVE-2026-74671

## What is CVE-2026-74671?

CVE-2026-74671 is a memory corruption vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ima: fix out-of-bounds read in xattr_verify()

The digest-length check in xattr_verify() mixes int and size_t:

	if (xattr_len - sizeof(xattr_value->type) - hash_start >=
			iint->ima_hash->length)

sizeof() yields size_t, so the usual arithmetic conversions promote
the whole left-hand side to unsigned 64-bit before the subtraction
runs. For a truncated xattr this underflows instead of going negative:
a 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1)
turns "1 - 1 - 1" into SIZE_MAX, which is trivially >= ima_hash->length.
The check then passes and the following memcmp() reads
iint->ima_hash->length bytes starting past the end of the buffer
vfs_getxattr_alloc() allocated for it.

Nothing upstream clamps xattr_len back into a safe range first:
ima_get_hash_algo() only special-cases xattr_len < 2 to pick a default
algorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than
failing when no HMAC key is loaded, so a truncated security.ima value
reaches the length check as-is.

Rewrite the comparison so every operand stays a signed int and no
implicit conversion to size_t can occur.

## Which versions are affected by CVE-2026-74671?


## How do I fix CVE-2026-74671?

Apply the vendor's patch.

## Is CVE-2026-74671 being exploited?

There is no known exploitation of CVE-2026-74671 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74671 and fix it if it is affected.

What it is: CVE-2026-74671 is a memory corruption vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74671 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74671/ (Markdown: https://insights.sbomify.com/CVE-2026-74671/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74671
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74671
- OSV: https://osv.dev/vulnerability/CVE-2026-74671

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74671/
Summaries are generated and may contain mistakes; the official description above is the record.