Unknown

CVE-2026-97922 — tracing: Free histogram var refs regardless of how often they are referenced

In the Linux kernel, the following vulnerability has been resolved: tracing: Free histogram var refs regardless of how often they are referenced Using the same variable three or more times in one hist trigger leaks the variable reference and its strings when the trigger is removed. commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy var_refs") made a trigger's var_refs[] array the only owner of a var ref: destroy_hist_field() returns early for HIST_FIELD_FL_VAR_REF, so the field expressions never destroy one. One entry, freed once, no count needed. commit 8bcebc77e85f ("tracing: Fix histogram code when expression has same var as value") then made repeated references share one object and added a count of them. Only the increment side exists, since those expressions still return early and never drop a reference, so __destroy_hist_field() sees how many references were created rather than how many are left. It frees when the decremented count is 0 or 1, so two references work and three or more leak. Sharing kept one array entry per object, and create_var_ref() searches and appends within a single trigger, so nothing outside it holds the object. Removing a trigger whose variables are still referenced is already refused by check_var_refs() with -EBUSY. Drop the count and free unconditionally.

Published Sep 25, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.21%

ahead of 10% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < a1f1d64a0a9791c842c4646253daf6ac0313eac7≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < b513a4c60a7aa1f4b4c2a48544ab003cb36f1e94≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < e7b6d67b43caee9183a4374d23641578ea556e6c≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < 4cff53bb19412c6f2d90b50678de5c3903f7f96a≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < 94bbd65da4ae26592fa1977a74ee94218ab02a26≥ 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 and < 4bddcb346a6cf4615ca77f69a589623b877ca267version ce28d664054df01997baace61d1defca77689798version bf470f051556b610265ea02ad2102de75e8e619c and 3 more ≥ 4.19.100 and < 4.20≥ 5.4.16 and < 5.5version 5.5	Vulnerable	CVE Program (cve.org) e CISA ADP

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 25, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

6 on the record

git.kernel.org/stable/c/4cff53bb19412c6f2d90b50678de5c3903f7f96a
NIST National Vulnerability Database
git.kernel.org/stable/c/a1f1d64a0a9791c842c4646253daf6ac0313eac7
NIST National Vulnerability Database
git.kernel.org/stable/c/94bbd65da4ae26592fa1977a74ee94218ab02a26
NIST National Vulnerability Database
git.kernel.org/stable/c/e7b6d67b43caee9183a4374d23641578ea556e6c
NIST National Vulnerability Database
git.kernel.org/stable/c/b513a4c60a7aa1f4b4c2a48544ab003cb36f1e94
NIST National Vulnerability Database
git.kernel.org/stable/c/4bddcb346a6cf4615ca77f69a589623b877ca267
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 1d
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 1d
Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 2d
Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 2d
Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 2d
Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-97922 is "tracing: Free histogram var refs regardless of how often they are referenced", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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