CVE-2026-105747 is a medium-severity (CVSS 4.3) CWE-409 vulnerability in docling. A fix is available for docling — see the affected versions and patch details below.
Docling: METS-GBS archive member limit enforced after full member enumeration (memory exhaustion during format detection)
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-105747.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-105747 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
docling🐍docling-slimReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When docling detects the input format of a gzip-compressed tar archive (METS-GBS), and later when the METS-GBS backend opens it, it calls tarfile.TarFile.getmembers(). That builds the full member list in memory before the max_member_count limit is checked. A small archive with a very large number of empty members therefore makes docling allocate memory in proportion to the member count, and the limit has no effect.
Details
docling/datamodel/document.py (format detection) and docling/backend/mets_gbs_backend.py both iterate tar.getmembers() and count members inside the loop. getmembers() reads every header up front.
Measured on Python 3.12: an archive of 1,000,000 empty members compresses to about 6.2 MB and makes getmembers() hold about 408 MB (about 66 times the input size). Format detection runs for any application/gzip input before allowed_formats is applied, so the allocation happens even when METS-GBS is not an allowed format.
This check was introduced by the fix for CVE-2026-44018 (GHSA-r3xg-rg9j-67fv) in 2.91.0. The eager enumeration it relies on has been there since METS-GBS detection was added in 2.45.0.
Impact
Memory exhaustion of the converting process, proportional to the size of the input archive. Confidentiality and integrity are not affected.
Patches
Fixed in docling 2.131.0 by #4412. Format detection and the METS-GBS backend now read archive members one at a time and stop as soon as max_member_count is exceeded, including when looking up page files.
Workarounds
Upgrade to 2.131.0. For older versions:
Reject gzip or tar inputs before they reach docling when METS-GBS support is not needed, and run conversions of untrusted input with memory limits.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | docling | ≥ 2.45.0&&< 2.131.0 | 2.131.0pip install --upgrade 'docling==2.131.0' |
| 🐍PyPI | docling-slim | ≥ 2.92.0&&< 2.131.0 | 2.131.0pip install --upgrade 'docling-slim==2.131.0' |
Affected Products
doclingdoclingDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for docling, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update docling to 2.131.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-105747 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
A MODERATE severity denial of service vulnerability was found in docling, a document conversion library shipped in Red Hat OpenShift AI (RHOAI) and Lightspeed Core products. When docling performs METS-GBS format detection on a gzip-compressed tar archive, and when the METS-GBS backend later opens it, the full archive…
A fix is available upstream in docling 2.131.0, which reads archive members incrementally and stops as soon as the member-count limit is exceeded. For deployments that cannot yet upgrade, the upstream project recommends rejecting gzip or tar inputs before they reach docling when METS-GBS support is not needed, and running conversions of untrusted input with memory limits so that excessive memory allocation cannot exhaust the host.Source: Red Hat security advisory for CVE-2026-105747 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-105747 in your dependencies?
Find it across PyPI, including transitive dependencies.