Unknown

CVE-2026-97923 — tracing: Free histogram the var ref when its initialization fails

In the Linux kernel, the following vulnerability has been resolved: tracing: Free histogram the var ref when its initialization fails create_var_ref() allocates a VAR_REF hist_field and then calls init_var_ref() to fill it in. When that fails the field is leaked. commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy var_refs") made destroy_hist_field() return early for HIST_FIELD_FL_VAR_REF, since var refs are freed by walking the trigger's var_refs[] array instead. create_var_ref() adds the field to that array only after init_var_ref() has succeeded, so on this path the field is in neither place and nothing frees it. The call was correct when it was written, before var refs were taken out of destroy_hist_field(). init_var_ref() cannot free it either. The caller owns the field, so init_var_ref() undoes only its own string allocations and leaves the field alone. Freeing it there would leave create_var_ref() passing freed memory to destroy_hist_field(), which reads its flags. Call __destroy_hist_field(), which frees the field without consulting the flag.

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)+2

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 11% of scored CVEs · Oct 16, 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	≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 608b7751926ec08fae6a1ac4e7308195da68c362≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 4870f9071c9ea3c1423a07741b85a794db30d672≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 352f84a381e7b4651b30366e93cb858f3fa9c91a≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 4924328d6991f25b65bb7c8ff5d56c2a9b254851≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 74375caa20fe5165807b4334c783d1790b01f02a≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 222abcbe7866fef04563b6eb89fb21f627dcbc77≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < a69baeac38677270656e85753d93856a076dee57≥ 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 and < 516001d53e6b2ea95a251ee2ef54a1a689a3fd58 and 3 more version 836717841a30d7845cdf9cb806ee0ff3bfa7135a≥ 4.19.100 and < 4.20version 5.0	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 16, 2026 · 2 reading(s) · max 0.21%

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

8 on the record

git.kernel.org/stable/c/4870f9071c9ea3c1423a07741b85a794db30d672
NIST National Vulnerability Database
git.kernel.org/stable/c/4924328d6991f25b65bb7c8ff5d56c2a9b254851
NIST National Vulnerability Database
git.kernel.org/stable/c/222abcbe7866fef04563b6eb89fb21f627dcbc77
NIST National Vulnerability Database
git.kernel.org/stable/c/74375caa20fe5165807b4334c783d1790b01f02a
NIST National Vulnerability Database
git.kernel.org/stable/c/608b7751926ec08fae6a1ac4e7308195da68c362
NIST National Vulnerability Database
git.kernel.org/stable/c/516001d53e6b2ea95a251ee2ef54a1a689a3fd58
NIST National Vulnerability Database
git.kernel.org/stable/c/352f84a381e7b4651b30366e93cb858f3fa9c91a
NIST National Vulnerability Database
git.kernel.org/stable/c/a69baeac38677270656e85753d93856a076dee57
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-2026-97923 is "tracing: Free histogram the var ref when its initialization fails", 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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