High

CVE-2026-53223 — net: guard timestamp cmsgs to real error queue skbs

In the Linux kernel, the following vulnerability has been resolved: net: guard timestamp cmsgs to real error queue skbs skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb. If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents. Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership.

Published Jun 25, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.1% (30-day exploitation probability)+0
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.13%

ahead of 2% of scored CVEs · Oct 14, 2026

Affects

Linux

Linux and 1 more

CVSS base

7.1

High · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	version 4.11≥ 4.10.14 and < 4.11version cdaf15b43bd31003220cb080bcbbd57787a2fca9≥ 8605330aac5a5785630aec8f64378a54891937cc and < 1ee90b77b727df903033db873c75caac5c27ec98≥ 8605330aac5a5785630aec8f64378a54891937cc and < eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a≥ 8605330aac5a5785630aec8f64378a54891937cc and < 3dde4fb941fa5649ab809f6cd3e20e0c424a4e31≥ 8605330aac5a5785630aec8f64378a54891937cc and < e0665b2a8e90bb08bd205062c75662b502d31797≥ 8605330aac5a5785630aec8f64378a54891937cc and < b903e9b5629ec8dd6db92174070045bf81ad7060 and 3 more ≥ 8605330aac5a5785630aec8f64378a54891937cc and < ad9a0374ee6d11048e1f74cd5180bad58b9848b4≥ 8605330aac5a5785630aec8f64378a54891937cc and < 71ff5cdd5da61d0438e902aa0fd68c28bc901abe≥ 8605330aac5a5785630aec8f64378a54891937cc and < 24a0d548d3a765cd4558224e4f8e06e14cba26e3	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	version 7.1-rc3version 7.1-rc7version 7.1-rc6version 7.1-rc5version 7.1-rc4≥ 4.10.14 and < 4.11version 7.1-rc2version 7.1-rc1 and 13 more version 4.11-rc8version 4.11-rc7version 4.11-rc6version 4.11-rc5version 4.11-rc4version 4.11≥ 6.19 and < 7.0.13≥ 6.13 and < 6.18.36≥ 6.7 and < 6.12.94≥ 6.2 and < 6.6.143≥ 5.16 and < 6.1.176≥ 5.11 and < 5.15.210≥ 4.11.1 and < 5.10.259	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.1	CVSS 3.1	High	1.8	5.2	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.1	CVSS 3.1	High	—	—	GitHub, Inc. via GitHub Security Advisories
7.1	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.13%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 7.1
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 25, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

12 on the record

git.kernel.org/stable/c/e0665b2a8e90bb08bd205062c75662b502d31797
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/3dde4fb941fa5649ab809f6cd3e20e0c424a4e31
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/ad9a0374ee6d11048e1f74cd5180bad58b9848b4
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/1ee90b77b727df903033db873c75caac5c27ec98
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/b903e9b5629ec8dd6db92174070045bf81ad7060
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/71ff5cdd5da61d0438e902aa0fd68c28bc901abe
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/24a0d548d3a765cd4558224e4f8e06e14cba26e3
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a
Patch, NIST National Vulnerability Database
github.com/advisories/GHSA-9mph-4hqc-xqx7
GitHub Security Advisories
cert-portal.siemens.com/productcert/html/ssa-457936.html
NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-019113.html
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-53223
GitHub Security Advisories

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-53223 is "net: guard timestamp cmsgs to real error queue skbs", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 describes technical severity. EPSS 0.13% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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