CVE-2024-26993 — fs: sysfs: Fix reference leak in sysfs_break_active_protection()
In the Linux kernel, the following vulnerability has been resolved: fs: sysfs: Fix reference leak in sysfs_break_active_protection() The sysfs_break_active_protection() routine has an obvious reference leak in its error path. If the call to kernfs_find_and_get() fails then kn will be NULL, so the companion sysfs_unbreak_active_protection() routine won't get called (and would only cause an access violation by trying to dereference kn->parent if it was called). As a result, the reference to kobj acquired at the start of the function will never be released. Fix the leak by adding an explicit kobject_put() call when kn is NULL.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+3
- Technical severity (medium)+3
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.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
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, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- 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 |
version c984f4d1d40a2f349503b3faf946502ccbf02f9f≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < 5d43e072285e81b0b63cee7189b3357c7768a43b≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < ac107356aabc362aaeb77463e814fc067a5d3957≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < a4c99b57d43bab45225ba92d574a8683f9edc8e4≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < a90bca2228c0646fc29a72689d308e5fe03e6d78version e8a37b2fd5b5087bec6cbbf6946ee3caa712953bversion a6abc93760dd07fcd29760b70e6e7520f22cb288version 461a6385e58e8247e6ba2005aa5d1b8d980ee4a2 and 13 moreversion 8a5e02a0f46ea33ed19e48e096a8e8d28e73d10a≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < 43f00210cb257bcb0387e8caeb4b46375d67f30cversion 807d1d299a04e9ad9a9dac55419c1137a105254b≥ 3.16.62 and < 3.17≥ 3.18.121 and < 3.19≥ 4.4.154 and < 4.5≥ 4.9.125 and < 4.10≥ 4.14.68 and < 4.15≥ 4.18.6 and < 4.19version 4.19≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < 84bd4c2ae9c3d0a7d3a5c032ea7efff17af17e17≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < 57baab0f376bec8f54b0fe6beb8f77a57c228063≥ 2afc9166f79b8f6da5f347f48515215ceee4ae37 and < f28bba37fe244889b81bb5c508d3f6e5c6e342c5 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
≥ 3.18.121 and < 3.19≥ 3.16.62 and < 3.17≥ 4.4.154 and < 4.5≥ 4.9.125 and < 4.10≥ 4.14.68 and < 4.15≥ 4.18.6 and < 4.19≥ 4.19 and < 5.15.157≥ 5.16 and < 6.1.88 and 6 more≥ 6.2 and < 6.6.29≥ 6.7 and < 6.8.8version 6.9-rc1version 6.9-rc2version 6.9-rc3version 6.9-rc4 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 5.5 | CVSS 3.1 | Medium | — | — | GitHub, Inc. via GitHub Security Advisories |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · linux/linux kernel
- CVSS changed · 5.5
- Source status changed · → Modified
- Record created in this database
- 2024
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
20 on the record
- git.kernel.org/stable/c/ac107356aabc362aaeb77463e814fc067a5d3957
- git.kernel.org/stable/c/5d43e072285e81b0b63cee7189b3357c7768a43b
- git.kernel.org/stable/c/a4c99b57d43bab45225ba92d574a8683f9edc8e4
- git.kernel.org/stable/c/f28bba37fe244889b81bb5c508d3f6e5c6e342c5
- git.kernel.org/stable/c/84bd4c2ae9c3d0a7d3a5c032ea7efff17af17e17
- git.kernel.org/stable/c/57baab0f376bec8f54b0fe6beb8f77a57c228063
- git.kernel.org/stable/c/43f00210cb257bcb0387e8caeb4b46375d67f30c
- git.kernel.org/stable/c/a90bca2228c0646fc29a72689d308e5fe03e6d78
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4EZ6PJ
- cert-portal.siemens.com/productcert/html/ssa-265688.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GCBZZE
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DAMSOZ
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4EZ6PJ
- lists.debian.org/debian-lts-announce/2024/06/msg00020.html
- cert-portal.siemens.com/productcert/html/ssa-613116.html
- lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- nvd.nist.gov/vuln/detail/CVE-2024-26993
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DAMSOZ
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GCBZZE
- github.com/advisories/GHSA-x5rp-2v68-jcgf
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 10h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 10h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
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 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-2024-26993 is "fs: sysfs: Fix reference leak in sysfs_break_active_protection()", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.27% 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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