Exploited CVEs / GNU / CVE-2023-4911
CVE-2023-4911
GNU C Library Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2023-12-12 (that deadline has passed); treat that date as the outer bound for your own environment. Check the vendor security advisory for the fix.
Risk summary
Actively exploited GNU C Library vulnerability, High severity, CVSS 7.8. Added to the CISA KEV catalog 2023-11-21.
Senserva AI Opinion for CVE-2023-4911
Known as Looney Tunables, this buffer overflow in the glibc dynamic loader's GLIBC_TUNABLES handling gives any local attacker root on mainstream Linux distributions, since ld.so underpins nearly every binary on the system. Its 81 percent EPSS is extraordinary for a local privilege escalation and reflects how universally the exploit works. CISA confirmed in-the-wild use, including by cloud-focused malware campaigns, in November 2023.
Do this: Confirm glibc is patched on every Linux server and container base image, rebuilding images that still carry 2023-era glibc.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2023-4911
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Updated August 14, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Full tracking and change history for CVE-2023-4911
- Published
- 2023-11-21
- Last revised
- 2023-11-21
- Changes tracked
- 3
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
- 2023-11-21 added to the CISA KEV catalog by CISA
- 2026-07-17 CVSS 0.0 to 7.8; EPSS first scored at 81.4%
Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.
CISA required action
Federal (BOD 22-01) remediation due date: 2023-12-12 (past due).
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Official fix for CVE-2023-4911
Check the vendor's security advisory channel for the patched GNU C Library versions and workarounds.
Common questions about CVE-2023-4911
Is CVE-2023-4911 actively exploited?
Yes. CVE-2023-4911 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-11-21, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 81%.
What is the CISA deadline and required action for CVE-2023-4911?
CISA set the federal (BOD 22-01) remediation due date at 2023-12-12, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
What fixes CVE-2023-4911?
Check the vendor's security advisory for the patched GNU C Library versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2023-4911?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2023-4911's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
Scope and sources
- More exploited GNU CVEs
All GNU exploited CVEs on one page: GNU vulnerabilities actively exploited.
- Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.