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CVE-2026-72057· NVD / CVE Program· CNA Linux

net/sched: act_ct: preserve tc_skb_cb across defragmentation

Noroxi assessment

Priority: Monitor (action score 32/100)

  • 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: 0.58% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 2400c4b05d58834b994500a9eec90a37db44187c, 5.15.217, 5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bac.

Low priority for now. Upgrade to Linux Linux 2400c4b05d58834b994500a9eec90a37db44187c, 5.15.217, 5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bac 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: net/sched: act_ct: preserve tc_skb_cb across defragmentation tcf_ct_handle_fragments() calls nf_ct_handle_fragments() without saving and restoring skb->cb. The defrag helper clears IPCB/IP6CB, which aliases the tc_skb_cb/qdisc_skb_cb control buffer. Fragmented traffic through act_ct therefore loses qdisc metadata such as pkt_segs and can trigger WARN_ON_ONCE() in qdisc_pkt_segs() when panic_on_warn is enabled. Save and restore the full tc_skb_cb around nf_ct_handle_fragments(), matching the pattern used by ovs_ct_handle_fragments().

HighCVSS 8.2 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 19, 2026
EPSS
0.5% · 47th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.2
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.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

    • 5.16affected
    • 0d76daf2013ce1da20eab5e26bd81d983e1c18fb and later · before fb080b6f54835d5d4d11ce3122800e6f0f6689e6affected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before 67d6b00a54446c008f52cf70fc0c2ad0c712f85daffected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before 2400c4b05d58834b994500a9eec90a37db44187caffected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before 5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bacaffected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before b3d835407846134b0d54637c0281b39bebef831daffected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before f7f45ceb855d9ba1cba594fb3f383255f7013fadaffected · git
    • ec624fe740b416fb68d536b37fb8eef46f90b5c2 and later · before 9092e15defbe6c7bc241c306093ca9d358a578e7affected · git
    • 5.15.13 and later · before 5.15.217affected · semver
    • before 5.16not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:13linuxbefore 6.12.100-16.12.100-1
Debian:14linuxbefore 7.1.5-17.1.5-1

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-2026-72054Aug 15, 2026 · net: ip_vti: require CAP_NET_ADMIN in the device netns for changelink
    35Monitor
  • ← EarlierCVE-2026-72055Aug 15, 2026 · net: ip6_vti: require CAP_NET_ADMIN in the device netns for changelink
    35Monitor
  • Later →CVE-2026-72061Aug 15, 2026 · net: sit: require CAP_NET_ADMIN in the device netns for changelink
    35Monitor

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 Linux2400c4b05d58834b994500a9eec90a37db44187cVendor (CNA)
Linux Linux5.15.217Vendor (CNA)
Linux Linux5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bacVendor (CNA)
Linux Linux67d6b00a54446c008f52cf70fc0c2ad0c712f85dVendor (CNA)
Linux Linux9092e15defbe6c7bc241c306093ca9d358a578e7Vendor (CNA)
Linux Linuxb3d835407846134b0d54637c0281b39bebef831dVendor (CNA)
Linux Linuxf7f45ceb855d9ba1cba594fb3f383255f7013fadVendor (CNA)
Linux Linuxfb080b6f54835d5d4d11ce3122800e6f0f6689e6Vendor (CNA)
debian:linux6.1.187-1 · 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.

  • CVE-2025-68775214 days apartnet/handshake: duplicate handshake cancellations leak socket
    39Monitor
  • CVE-2026-6383227 days apartwifi: mt76: add wcid publish check in mt76_sta_add
    35Monitor
  • CVE-2026-681495 days apartfs: preserve ACL_DONT_CACHE state in forget_cached_acl()
    33Monitor
  • CVE-2026-684045 days apartwifi: cfg80211: use wiphy work for socket owner autodisconnect
    31Monitor
  • CVE-2026-6455617 days apartperf/core: Detach event groups during remove_on_exec
    31Monitor
  • CVE-2026-681035 days apartdrm/amdgpu: reject mapping a reserved doorbell to a new queue
    28Monitor

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-662 · Improper Synchronization

CVSS vector

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

Change log

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

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

References

Show all references (6 more)

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

All records