CVE-2026-101955 Junos OS: SRX Series: Malformed DNS packet causes service disruption when UTM Anti-Spam SBL is used
Unauthenticated remote attackers can execute arbitrary code or cause denial of service via malformed DNS packets when UTM Anti-Spam SBL is enabled on Juniper SRX devices.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-101955?
CVE-2026-101955 is a critical memory corruption vulnerability in Juniper Networks Junos OS, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A Stack-based Buffer Overflow vulnerability in the UTM Anti-Spam SBL of Juniper Networks Junos OS on SRX series allows an unauthenticated remote attacker to cause arbitrary code execution or a denial of service via a injected malformed DNS packet when Anti-Spam SBL inspection is enabled.
Weakness: CWE-121
Which versions are affected by CVE-2026-101955?
How do I fix CVE-2026-101955?
No fix has been published for CVE-2026-101955 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-101955 being exploited?
There is no known exploitation of CVE-2026-101955 in the wild and no public exploit code.
Sources
Also known as GHSA-rqrg-xm4f-h8pg.