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CVE-2026-89487· NVD / CVE Program· CNA Linux

openvswitch: only skb_tx_error() a packet we are about to drop

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0dbc2398fca3bb33eda963849f865ddb1b3aa05e, 3.11, 3.13; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0dbc2398fca3bb33eda963849f865ddb1b3aa05e, 3.11, 3.13; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: openvswitch: only skb_tx_error() a packet we are about to drop queue_userspace_packet() borrows the packet skb -- it only copies it into a private netlink message (user_skb) and does not own it; on return do_execute_actions() keeps forwarding it through the flow's remaining actions. Its error path nevertheless calls skb_tx_error(skb), which via skb_zcopy_clear() does skb_shinfo(skb)->flags &= ~SKBFL_ALL_ZEROCOPY, stripping SKBFL_SHARED_FRAG from that live skb (skb_tx_error()'s kerneldoc says "skb must be freed afterwards"). For a MSG_ZEROCOPY skb carrying page-cache frags, SKBFL_SHARED_FRAG is what makes esp_input() skb_cow_data() before in-place AEAD; once it is stripped a later local ESP-in-UDP delivery decrypts in place over pages the sender does not own -- an unprivileged page-cache write (the "Fragnesia" primitive). do_execute_actions() ignores output_userspace()'s return value, so any action after a failed USERSPACE upcall inherits the stripped skb. Move the skb_tx_error() to the flow-miss drop path - the "default" branch of ovs_dp_process_packet()'s switch(error), before kfree_skb(). The call has been here since commit 36d5fe6a0007 ("core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle errors") but was harmless until esp_input() began relying on SKBFL_SHARED_FRAG to gate in-place decrypt; only then did stripping it on a still-forwarded skb become a page-cache write primitive.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • c5f0c0e7525443add533495e93ba8de6feab2396, 1674b4bf3eea3cac51b70778e89f8025f7cfe695, 3.14affected
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 5de5d554141a15b3f1f5c978fd9f7f4fd6d0600aaffected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 48db11e115d1b232edc5591604adc6eda95cd545affected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 4477222e2916a18e273edc139c955ade6bbb7a69affected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 4d5c460ef8754be1d43b16dbf02695b008b207d6affected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 6767d70cf46f65807a6a4c4406a518e6c12e36aeaffected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before e41a59fc056f63a7a1f42788913c53cc48d744aaaffected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 5d85eef222cfd28e73deed7402c100229e8b9e6eaffected · git
    • 36d5fe6a000790f56039afe26834265db0a3ad4c and later · before 0dbc2398fca3bb33eda963849f865ddb1b3aa05eaffected · git
    • 3.10.51 and later · before 3.11affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-89485Sep 11, 2026 · lockd: pin next file across nlm_inspect_file lock-drop
    39Monitor
  • ← EarlierCVE-2026-89486Sep 11, 2026 · ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
    31Monitor
  • Later →CVE-2026-89488Sep 11, 2026 · openvswitch: Fix CT limit teardown use-after-free
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0dbc2398fca3bb33eda963849f865ddb1b3aa05eVendor (CNA)
Linux Linux3.11Vendor (CNA)
Linux Linux3.13Vendor (CNA)
Linux Linux4477222e2916a18e273edc139c955ade6bbb7a69Vendor (CNA)
Linux Linux48db11e115d1b232edc5591604adc6eda95cd545Vendor (CNA)
Linux Linux4d5c460ef8754be1d43b16dbf02695b008b207d6Vendor (CNA)
Linux Linux5d85eef222cfd28e73deed7402c100229e8b9e6eVendor (CNA)
Linux Linux5de5d554141a15b3f1f5c978fd9f7f4fd6d0600aVendor (CNA)
Linux Linux6767d70cf46f65807a6a4c4406a518e6c12e36aeVendor (CNA)
Linux Linuxe41a59fc056f63a7a1f42788913c53cc48d744aaVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records