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Fencer Vulns
low 2.1

CVE-2026-77831 json

Algorithmic-complexity denial of service in AshPaperTrail full-diff list tracking

published 2026-08-30 2 mo ago modified 2026-09-08 2 mo ago also EEF-CVE-2026-77831 , GHSA-7c66-59m8-723c , EUVD-2026-68144

cvss
2.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

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.

Patch / fix

  • hex ash_paper_trail 0.7.0
  • ash-project ash_paper_trail 0.7.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ash-project/ash_paper_trail/security/advisories/GHSA-7c66-59m8-723c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 2.1 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CNA 4.0 2.1 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
hex ash_paper_trail
>=0.1.1, <0.7.0
0.7.0

Affected products

  • ash-project ash_paper_trail

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.