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CVE Record

CVE-2026-43481: net-shapers: don't free reply skb after genlmsg_reply()

In the Linux kernel, the following vulnerability has been resolved: net-shapers: don't free reply skb after genlmsg_reply() genlmsg_reply() hands the reply skb to netlink, and netlink_unicast() consumes it on all return paths, whether the skb is queued successfully or freed on an error path. net_shaper_nl_get_doit() and net_shaper_nl_cap_get_doit() currently jump to free_msg after genlmsg_reply() fails and call nlmsg_free(msg), which can hit the same skb twice. Return the genlmsg_reply() error directly and keep free_msg only for pre-reply failures.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel error can free the same network-related memory object twice after a reply fails. A locally authenticated, low-privileged user may be able to trigger memory corruption, potentially affecting confidentiality, integrity, and availability. The supplied CVSS score is 7.8, rated high.

Executive priority

Treat as a high-priority kernel update for multi-user or otherwise locally exposed Linux systems. Internet reachability alone does not create the stated attack path, but successful local exploitation could compromise the entire host. Confirm exposure promptly because the supplied affected-version representation is incomplete or ambiguous.

Technical view

The affected net-shaper Generic Netlink handlers call nlmsg_free() after genlmsg_reply() fails, although netlink_unicast() has already consumed or freed the socket buffer on every return path. The cited fix returns the reply error directly, preventing a double free.

Likely exposure

Exposure requires a Linux kernel containing the vulnerable net-shaper handlers and local low-privileged access. The bundle’s version data is ambiguous, so exact vulnerable ranges should be confirmed through vendor advisories, distribution backports, or comparison with the cited fixes.

Exploitation context

The CVSS vector indicates local, low-complexity exploitation requiring low privileges and no user interaction, with potential high impact across all three security objectives. The bundle reports no KEV listing and provides no evidence of active exploitation or a public exploit.

Researcher notes

The defect is a post-genlmsg_reply() error-path double free in net_shaper_nl_get_doit() and net_shaper_nl_cap_get_doit(). The three stable-kernel commits are the strongest remediation references supplied. No CWE, exploit proof, or detailed affected-range mapping is provided, limiting certainty about branch-specific exposure.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable cited stable fix.
  • Review Linux distribution advisories for backported fixes and corrected version ranges.
  • Restrict unnecessary local account and workload access until affected systems are updated.
  • Prioritize shared or multi-user Linux hosts where untrusted users receive local access.

Validation and detection

  • Inventory kernel versions across Linux hosts, containers, and virtual machines.
  • Confirm installed kernels include an applicable cited fix or vendor backport.
  • Verify systems rebooted into the corrected kernel after installation.
  • Review crash and kernel logs for unexplained netlink or memory-corruption events.
Prepared
Confidence
medium
Sources
5

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

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CVE-2026-43481 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
0ADP providers
4Source links

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-2026-43481Attack 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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux4b623f9f0f59652ea71fcb27d60b4c3b65126dbb, 4b623f9f0f59652ea71fcb27d60b4c3b65126dbb, 4b623f9f0f59652ea71fcb27d60b4c3b65126dbbunaffected
LinuxLinux6.13, 0, 6.18.19, 6.19.9, 7.0affected
Weakness

CWE details

No CWE listed

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