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CVE Record

CVE-2024-26739: net/sched: act_mirred: don't override retval if we already lost the skb

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: don't override retval if we already lost the skb If we're redirecting the skb, and haven't called tcf_mirred_forward(), yet, we need to tell the core to drop the skb by setting the retcode to SHOT. If we have called tcf_mirred_forward(), however, the skb is out of our hands and returning SHOT will lead to UaF. Move the retval override to the error path which actually need it.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A local, low-privileged user may trigger a use-after-free in Linux traffic-control packet redirection. Successful exploitation could crash the system or potentially compromise kernel confidentiality and integrity. The supplied CVSS score is 7.8 (High).

Executive priority

Treat as a high-priority kernel update for exposed multi-user Linux systems. Expedite systems permitting untrusted local access; handle tightly controlled single-user systems through the normal urgent patch cycle after confirming affected versions.

Technical view

The act_mirred traffic-control action could return SHOT after tcf_mirred_forward() had already transferred ownership of the network packet buffer. The core could then access or release an object no longer owned by that path, causing a use-after-free. The fix limits the return-code override to the error path that still owns the buffer.

Likely exposure

Exposure requires local, low-privileged access to a system running an affected Linux kernel and a reachable traffic-control mirred path. The bundle lists several affected releases, but its version data is not a complete, clearly bounded range; confirm status through kernel or distribution advisories.

Exploitation context

The supplied CVSS vector indicates local attack access, low complexity, low privileges, no user interaction, and potentially high confidentiality, integrity, and availability impact. The bundle marks KEV false and provides no cited evidence of active exploitation or public weaponization.

Researcher notes

The vulnerable condition concerns skb ownership after mirred forwarding and an incorrect SHOT return. The bundle supplies multiple stable-branch commits but does not map each commit to an explicit version range. It also provides no CWE, proof of concept, or exploitation evidence, so branch-level exposure requires vendor confirmation.

Mitigation direction

  • Install a vendor-supported kernel update incorporating the referenced upstream stable fix.
  • Review Linux distribution advisories for the exact fixed package version on each supported release.
  • Prioritize multi-user hosts where untrusted or low-privileged users have local access.
  • Restrict unnecessary local accounts while updates are pending.

Validation and detection

  • Inventory running kernel versions across Linux hosts.
  • Compare installed packages with applicable kernel or distribution security advisories.
  • Confirm the deployed kernel contains the relevant stable fix for its branch.
  • Reboot updated systems and verify the fixed kernel is running.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2024-26739 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-26739Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe5cf1baf92cb785b90390db1c624948e70c8b8bd, e5cf1baf92cb785b90390db1c624948e70c8b8bd, e5cf1baf92cb785b90390db1c624948e70c8b8bd, e5cf1baf92cb785b90390db1c624948e70c8b8bd, e5cf1baf92cb785b90390db1c624948e70c8b8bd, e5cf1baf92cb785b90390db1c624948e70c8b8bdunaffected
LinuxLinux4.19, 0, 5.10.238, 5.15.182, 6.1.136, 6.6.19, 6.7.7, 6.8affected
Weakness

CWE details

No CWE listed

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