CVE-2026-55777 GoAccess: Out-of-bounds heap read in parse_ios() via crafted User-Agent leads to remote crash/DoS
A crafted User-Agent string in access logs triggers an out-of-bounds heap read in GoAccess, causing a remote crash and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55777?
CVE-2026-55777 is a medium-severity memory corruption vulnerability in allinurl goaccess, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
GoAccess is a real-time web log analyzer and interactive viewer that runs in a terminal in *nix systems or through the browser. Prior to 1.11, the parse_ios() function uses an attacker-controlled keyword-to-OS offset as both the source offset and copy length for memmove, allowing a crafted User-Agent in a processed access log to read up to approximately 4 KB beyond the heap allocation and conditionally crash GoAccess. This issue is fixed in version 1.11.
Weakness: CWE-125
Which versions are affected by CVE-2026-55777?
How do I fix CVE-2026-55777?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-55777 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55777 exists.
Sources
Also known as DEBIAN-CVE-2026-55777, GHSA-5phr-qpgf-hgrg, UBUNTU-CVE-2026-55777.