CVE-2026-90151 (CVSS 9.8)

Description

In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0074

Probability of exploitation

0.54%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/3f2387e8bfbc4efda5d77c3a11a028d0a119c48f https://git.kernel.org/stable/c/5891c03e150920618db0e9c4ea2d772abacdcfd1 https://git.kernel.org/stable/c/68c721391b761dbe38d5b0094d2bb6e8489ad92b https://git.kernel.org/stable/c/7c4812eb96bdcafb31a65b12f2aa96659429d1d4 https://git.kernel.org/stable/c/80b1c3d5a881f7d9081aa9f46da9742878a0f893 https://git.kernel.org/stable/c/9bfdd0f591307b5198826a0e7a5b2f35f87acd2d https://git.kernel.org/stable/c/d05c2007b3d84ccba11dc6e9cb3202768cc72f14 https://git.kernel.org/stable/c/fc95ca82d5ae598c428ab5a00ae69f8526d59371

Frequently Asked Questions

What is CVE-2026-90151? +

In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-90151? +

CVE-2026-90151 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0074, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-90151? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-90151