# CVE-2026-119205: pypdf: Possible infinite loop when cloning dictionaries


- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 29 Oct 2026
- **Updated:** 29 Oct 2026

## What is CVE-2026-119205?

CVE-2026-119205 is a high-severity vulnerability in py-pdf pypdf, published on 29 Oct 2026. 

### Official description

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop when cloning or duplicating a crafted cyclic DictionaryObject. Clone traversal checked generated destination references rather than the original source references, allowing some source cycles to evade the visited-object check. This issue is fixed in version 6.21.4.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-119205?


## How do I fix CVE-2026-119205?

No fix has been published for CVE-2026-119205 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-119205 being exploited?

There is no known exploitation of CVE-2026-119205 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-119205 and fix it if it is affected.

What it is: CVE-2026-119205 is a high-severity vulnerability in py-pdf pypdf, published on 29 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-119205 in the wild and no public exploit code.

Affected product: py-pdf pypdf. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-119205/ (Markdown: https://insights.sbomify.com/CVE-2026-119205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-119205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-119205
- OSV: https://osv.dev/vulnerability/CVE-2026-119205

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-119205/
Summaries are generated and may contain mistakes; the official description above is the record.