CVE-2026-77831 Algorithmic-complexity denial of service in AshPaperTrail full-diff list tracking
An attacker can cause denial of service via excessive CPU and memory usage by submitting large array attributes to AshPaperTrail full-diff tracking.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-77831?
CVE-2026-77831 is a low-severity denial of service vulnerability in ash-project ash_paper_trail, published on 30 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Inefficient Algorithmic Complexity vulnerability in ash-project ash_paper_trail allows a user who can submit a large array attribute to a paper-trailed create or update action to cause a denial of service through excessive CPU and memory use.
With full-diff change tracking, AshPaperTrail.ChangeBuilders.FullDiff.ListChange pairs each prior array element against the new list by rebuilding the remaining-elements accumulator with acc ++ [tuple] on every step, copying the growing list each time, so the pairing scales cubically in the array length. Nothing bounds the length and the value comes straight from action input, so one request carrying a large accepted {:array, _} attribute forces tens of seconds of CPU and multi-gigabyte allocations.
This issue affects ash_paper_trail: from 0.1.1 before 0.7.0.
Weakness: CWE-407
Which versions are affected by CVE-2026-77831?
1 open source package ship an affected version, including ash_paper_trail.
| Package | Affected | Fixed in |
|---|---|---|
ash_paper_trail Hex | From 0.1.1 | 0.7.0 |
How do I fix CVE-2026-77831?
Upgrade ash_paper_trail to 0.7.0 or later.
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-2026-77831 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77831 exists.
Sources
Also known as EEF-CVE-2026-77831, GHSA-7c66-59m8-723c.