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CVE Record

CVE-2026-45929: ovpn: fix possible use-after-free in ovpn_net_xmit

In the Linux kernel, the following vulnerability has been resolved: ovpn: fix possible use-after-free in ovpn_net_xmit When building the skb_list in ovpn_net_xmit, skb_share_check will free the original skb if it is shared. The current implementation continues to use the stale skb pointer for subsequent operations: - peer lookup, - skb_dst_drop (even though all segments produced by skb_gso_segment will have a dst attached), - ovpn_peer_stats_increment_tx. Fix this by moving the peer lookup and skb_dst_drop before segmentation so that the original skb is still valid when used. Return early if all segments fail skb_share_check and the list ends up empty. Also switch ovpn_peer_stats_increment_tx to use skb_list.next; the next patch fixes the stats logic.

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 flaw in OpenVPN data transmission can reuse memory after it has been freed. A local, low-privileged attacker may be able to crash the system or compromise confidentiality and integrity. Impact depends on whether an affected kernel and the ovpn transmit path are in use.

Executive priority

Treat as high priority on systems using affected ovpn functionality, especially multi-user or less-trusted hosts. Expedite validated kernel updates, but current evidence does not support declaring an internet-wide emergency or active exploitation campaign.

Technical view

In ovpn_net_xmit, skb_share_check may free a shared original skb, but later operations dereference its stale pointer. The fix performs peer lookup and destination removal before segmentation, handles an empty segment list, and changes transmit statistics to reference skb_list.next.

Likely exposure

Potentially exposed systems run an affected Linux kernel and exercise the ovpn transmit path. The supplied metadata lists 6.16, 6.18.14, 6.19.4, and 7.0, but also contains ambiguous version data. Confirm exact distribution and backport status with vendors.

Exploitation context

The CVSS vector describes local access, low complexity, low privileges, and no user interaction, with potentially high confidentiality, integrity, and availability impact. The supplied record is not in KEV and provides no evidence of active exploitation or a public exploit.

Researcher notes

The defect is a transmit-path use-after-free involving shared skb handling after segmentation. Three Linux stable commits are referenced, likely reflecting branch-specific backports. Exact vulnerable and fixed release boundaries are not fully clear from the supplied version metadata; distribution-level confirmation is necessary.

Mitigation direction

  • Upgrade to a vendor-supported kernel containing the applicable stable fix.
  • Consult distribution advisories to confirm fixed package versions and backports.
  • Prioritize hosts that load or use the affected ovpn functionality.
  • Restrict local account access while remediation is pending.

Validation and detection

  • Record each host's running kernel and distribution package version.
  • Determine whether affected ovpn functionality is configured or active.
  • Verify the installed kernel includes the relevant stable fix or vendor backport.
  • Reboot into the corrected kernel and confirm the running version.
  • Monitor vendor advisories for clarified affected-version boundaries.
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-2026-45929 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-2026-45929Attack 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
LinuxLinux08857b5ec5d91d83e69e40a36554a8c7557b7301, 08857b5ec5d91d83e69e40a36554a8c7557b7301, 08857b5ec5d91d83e69e40a36554a8c7557b7301unaffected
LinuxLinux6.16, 0, 6.18.14, 6.19.4, 7.0affected
Weakness

CWE details

No CWE listed

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