CVE-2026-85977 Libtirpc: libtirpc: denial of service via unbounded memory allocation during portmapper response decoding
A remote attacker can cause a denial of service in applications using libtirpc by sending crafted portmapper responses that trigger unbounded memory allocation.
- 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-2026-85977?
CVE-2026-85977 is a medium-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 16 Oct 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
A flaw was found in libtirpc. A remote attacker can exploit this vulnerability by sending specially crafted PMAPPROC_DUMP replies to a client application that uses the pmap_getmaps() function against an attacker-controlled host. This unbounded decoding can lead to excessive memory and CPU allocation, causing the client process to experience a Denial of Service (DoS) due to resource exhaustion.
Weakness: CWE-1050
Which versions are affected by CVE-2026-85977?
Linux distribution packages (2)
libtirpc Red Hat:hummingbird:1 | All versions | 0:1.3.8-0.1.hum1 |
libtirpc-devel Red Hat:hummingbird:1 | All versions | 0:1.3.8-0.1.hum1 |
How do I fix CVE-2026-85977?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-85977 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85977 exists.
Sources
Also known as BELL-CVE-2026-85977, DEBIAN-CVE-2026-85977, ECHO-8a89-e7cc-2f31, GHSA-vc3g-5238-rmmw, RHSA-2026:80360, UBUNTU-CVE-2026-85977.