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NVD / CVE Program· CNA Linux

CVE-2026-90248: net/sched: cls_api: fix teardown of an adopted proto on insert-race loss

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 219c87aeefdcc8c1caf28cc99e9b361ce7393d3a, a68e664ddf16ecae6d769d6a2eb356f8abab75c9, bbe2fd6d77df630356185406a97317f6aa6a92cf.

Low priority for now. Upgrade to Linux Linux 219c87aeefdcc8c1caf28cc99e9b361ce7393d3a, a68e664ddf16ecae6d769d6a2eb356f8abab75c9, bbe2fd6d77df630356185406a97317f6aa6a92cf or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: fix teardown of an adopted proto on insert-race loss In tc_new_tfilter() the create branch sets tp_created = 1 before calling tcf_chain_tp_insert_unique(). When the caller loses the race (another request inserted a proto at the same chain/prio first), insert_unique() destroys the caller's own tp_new and returns the winner's proto with an extra reference. tp_created was never cleared, so the loser's errout path treated the winner's live proto as its own and called tcf_chain_tp_delete_empty() on it, silently unlinking an active classifier that the winning request already advertised via RTM_NEWTFILTER. Track the outcome of the insert step in a single tri-state variable so each errout path reacts correctly: - TP_NOT_CREATED: no proto created; pursue the old path. - TP_CREATED: proto inserted successfully; same code path as before. - TP_NOT_OWNED: New - lost the insert race; tp is another request's proto (chain ref already released by tp_new's destroy) Both errout reactions are single expressions derived from the state. This fix is motivated by the Sashiko's automated review of Patch (net/sched: cls_api: Always acquire rtnl_lock when destroying locked classifiers) [1][2]. The review identified the silent-unlink behaviour of an adopted proto's teardown when a request loses the tcf_chain_tp_insert_unique() race. [1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com [2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

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—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.1affected
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before a68e664ddf16ecae6d769d6a2eb356f8abab75c9affected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before df02b6dc136af45e92ee4c86f4aa6c9a60790b1eaffected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before bee2208276c8e0e40a249ffdcf6e5434a79a847caffected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before 219c87aeefdcc8c1caf28cc99e9b361ce7393d3aaffected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before bbe2fd6d77df630356185406a97317f6aa6a92cfaffected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before dc8b33b819cb02a75936940c120aa669ad89942daffected · git
    • 8b64678e0af8f4d62a40149baedebe78503a5255 and later · before d4e359b3608a0e184bbe8d61a5c3b50d0831c44aaffected · git
    • before 5.1not affected · semver
    • 5.15.221 and later · up to and including 5.15.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    40Plan
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  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90246Sep 17, 2026 · apparmor: fix integer overflow in verify_tags() bounds check
    28Monitor
  • ← EarlierCVE-2026-90247Sep 17, 2026 · bpf: Fix mmap_lock leak in irq_work path
    0Monitor
  • Later →CVE-2026-90249Sep 17, 2026 · iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux219c87aeefdcc8c1caf28cc99e9b361ce7393d3aVendor (CNA)
Linux Linuxa68e664ddf16ecae6d769d6a2eb356f8abab75c9Vendor (CNA)
Linux Linuxbbe2fd6d77df630356185406a97317f6aa6a92cfVendor (CNA)
Linux Linuxbee2208276c8e0e40a249ffdcf6e5434a79a847cVendor (CNA)
Linux Linuxd4e359b3608a0e184bbe8d61a5c3b50d0831c44aVendor (CNA)
Linux Linuxdc8b33b819cb02a75936940c120aa669ad89942dVendor (CNA)
Linux Linuxdf02b6dc136af45e92ee4c86f4aa6c9a60790b1eVendor (CNA)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records