[UPDATE] [medium] GNU libc: Multiple vulnerabilities allow manipulation of DNS responses
A remote, anonymous attacker can exploit multiple vulnerabilities in GNU libc to manipulate DNS responses.
CSIRTS triage
- What
- Multiple vulnerabilities in GNU libc allow manipulation of DNS responses by remote attackers.
- Who is affected
- Deployments using GNU libc are affected by these vulnerabilities.
- Urgency
- Remediation is medium urgency as the vulnerabilities can be exploited remotely but are not currently known to be actively exploited.
- Action
- Users should update to the latest version of GNU libc.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-0817
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-44370.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 25% of all scored CVEs.
- Low exploitation riskCVE-2026-44380.32% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 24% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-4437 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-4438 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownUSN-8611-1: GNU C Library vulnerabilitiesubuntu
Recent advisories for GNU libc
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- critical[UPDATE] [critical] GNU libc: Multiple vulnerabilitiescert-bund · 2026-07-30
- medium[UPDATE] [medium] GNU libc: Multiple vulnerabilitiescert-bund · 2026-07-30
- medium[UPDATE] [medium] GNU libc: Vulnerability allows denial of servicecert-bund · 2026-07-28
- medium[UPDATE] [medium] GNU libc: Vulnerability Allows Denial of Servicecert-bund · 2026-07-21
- medium[UPDATE] [medium] GNU libc: Vulnerability allows information disclosurecert-bund · 2026-07-16
More from CERT-Bund (BSI) Security Advisories
- medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of service2026-07-31
- medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow Denial of Service2026-07-31
- medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of service2026-07-31
- medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities2026-07-31
- medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow unspecified attack2026-07-31