CVE-2026-5435: Potential buffer overflow in ns_sprintrrf TSIG handling path

highCVSS 8.6CVE-2026-5435

CSIRTS triage

Memory corruption

What: A potential buffer overflow exists in ns_sprintrrf TSIG handling path, likely in DNS or DNS-related software.
Who is affected: Systems using affected DNS software with TSIG (Transaction Signature) support.
Urgency: High severity (CVSS 8.6) and not exploited; buffer overflows can lead to remote code execution and warrant immediate attention.
Action: Identify and patch the affected DNS implementation (likely BIND or similar); check vendor advisories for specific versions and patches.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 8.6
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-5435

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-2026-54350.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-5435	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] GNU libc: Multiple vulnerabilitiescert-bund
unknownUSN-8611-1: GNU C Library vulnerabilitiesubuntu

Recent advisories for Potential buffer overflow

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.

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