CVE-2023-2640

On Ubuntu kernels carrying both c914c0e27eb0 and "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.* xattrs", an unprivileged user may set privileged extended attributes on the mounted files, leading them to be set on the upper files without the appropriate security checks.

CVSS: 7.8Highscored by the publisher (CNA)
Exploited in the wild: Not knownPublic exploit code; not in CISA KEV
EPSS: 15.2%chance of exploitation in the next 30 daystop 4% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 26 Jul 2023analysed here 12 Nov 2026

Summary

Triage

Attack surface: Server-side
Exploitable: At runtime
Attack vector: local
Weakness: CWE-863 Incorrect Authorization
Can a WAF block it?: No. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Products named in our analysis

canonical:ubuntu_linux

Fix and mitigation

WAF and other mitigations

Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.

Also consider: patch · per-resource ACL

Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Not listed as of our last sync.
Public exploit code: Yes: 1 Metasploit module · 10 GitHub proofs of concept
CISA SSVC: exploitation none, automatable no, technical impact totalAssessed by CISA 23 Oct 2024 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Metasploit

exploit/linux/local/gameoverlay_privescexploit, rank normal

GitHub proofs of concept

g1vi/CVE-2023-2640-CVE-2023-32629137 stars
luanoliveira350/GameOverlayFS17 stars
OllaPapito/gameoverlay13 stars
musorblyat/CVE-2023-2640-CVE-2023-326292 stars

and 6 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

26 Jul 2023Published
15 Aug 2023First public exploit or proof of concept20 days later
23 Oct 2024CISA SSVC assessment: exploitation none436 days (about 1 year) later
23 Oct 2024CVE record last updatedsame day later
12 Nov 2026Analysed by vulneraibility.com750 days (about 2 years) later

CVSS vector

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

Metric	Value	What it means
Attack vector	LocalLocal access required (shell, logged-in user).	Local access required (shell, logged-in user).
Attack complexity	LowRepeatable attack, no special conditions.	Repeatable attack, no special conditions.
Privileges required	LowThe attacker needs basic user privileges.	The attacker needs basic user privileges.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	HighTotal data disclosure possible.	Total data disclosure possible.
Integrity	HighComplete modification possible.	Complete modification possible.
Availability	HighFull outage possible.	Full outage possible.

Common questions

Is CVE-2023-2640 being exploited?

Not confirmed. CVE-2023-2640 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 15% probability of exploitation in the next 30 days.

How severe is CVE-2023-2640?

CVE-2023-2640 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2023-2640?

Yes. A fix has been recorded for CVE-2023-2640. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2023-2640 affect?

CVE-2023-2640 affects canonical:ubuntu_linux. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

4 references in the CVE record, grouped by the tags the record gives them.

Advisories (1)

ubuntu.com /security/notices/USN-6250-1

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Metasploit Framework: exploit and scanner modules
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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