VulnerabilityPublished 15 Aug 2026Updated 9 Oct 2026

CVE-2026-74290: Linux kernel · net/sched: cls_flow: Dont expose folded kernel pointers

Affects Linux kernelSource GCVE Database

Not known to be exploited · fixed in 7.0.0-1014.14~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.0-1014.14~24.04.1, 7.0.0-1017.17~24.04.1, 7.0.0-1016.16~24.04.1 +11

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-wfqw-582v-82vh

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected <7.0.0-38.38	Fixed in 7.0.0-38.38
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected <7.0.0-1017.17	Fixed in 7.0.0-1017.17
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected <7.0.0-1016.16	Fixed in 7.0.0-1016.16
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected <7.0.0-1008.9	Fixed in 7.0.0-1008.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available that replaces the insecure XOR folding with a cryptographically secure keyed siphash in the Linux kernel's cls_flow component. Users should apply the official kernel updates that include this fix. No additional mitigation steps are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's net/sched cls_flow component allowed exposure of folded kernel pointers due to the use of an insecure XOR folding method. This flaw enabled a user or network namespace to recover 32-bit folded values of kernel pointers, potentially leaking sensitive kernel memory information. The issue was resolved by replacing the XOR folding with a cryptographically secure keyed siphash, aligning with standard kernel pointer hashing practices. Multiple specific Linux kernel versions are affected. A patch is available to address this vulnerability.

Impact

An attacker with access to a tc classifier in a user or network namespace could recover folded kernel pointer values, potentially leaking sensitive kernel memory information. This could aid in further attacks that rely on kernel address information. However, there is no indication of direct code execution or privilege escalation solely from this vulnerability. The impact is primarily information disclosure of kernel pointers.

Summary

The Linux kernel's flow classifier (cls_flow) used addr_fold() to fold kernel pointers for fields missing from packet headers. In map mode, userspace controls parameters that influence the folding process and can observe the resulting classid via class statistics. This allowed a tc classifier in a user or network namespace to recover the 32-bit folded values of kernel pointers such as skb->sk, skb_dst(), or skb_nfct(). The vulnerability was due to the use of XOR folding, which is not cryptographically secure. The fix replaces XOR folding with a keyed siphash, preventing exposure of kernel pointer information and aligning with standard kernel pointer hashing practices.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 09:01 UTC

Technical details

References

Community reviews

Related threats