# pypdf: Inefficient decoding of FlateDecode PNG predictor streams

Advisory record · `GHSA-5hgr-hg42-57jg`

- **Identifiers:** `GHSA-5hgr-hg42-57jg` · `CVE-2026-49460` · `PYSEC-2026-3010`
- **State:** Confirmed
- **Severity:** CVSS 5.1 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-407](https://cwe.mitre.org/data/definitions/407.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 16 Jun 2026
- **Updated:** 13 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 16 Jun 2026, 13:46 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `pypdf` (PyPI): affected `<6.12.2`; fixed in `6.12.2`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> pypdf versions before 6.12.2 are vulnerable to inefficient decoding of FlateDecode streams that use a PNG predictor. An attacker who supplies a crafted PDF can cause long processing runtimes when such a stream is accessed. Upgrade to pypdf 6.12.2 or later. The source gives no workaround the reader can apply directly other than the upstream patch.

Written 6 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.1 Medium, CVSS 4.0: `CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0017, the 5th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 22 Jun 2026, 21:16 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-49460)
- 31 Oct 2026, 15:03 UTC: First seen by agentprime
- 31 Oct 2026, 15:03 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5hgr-hg42-57jg)

## Sources

- [GitHub Advisory Database: GHSA-5hgr-hg42-57jg](https://github.com/advisories/GHSA-5hgr-hg42-57jg)
- [OSV: GHSA-5hgr-hg42-57jg](https://osv.dev/vulnerability/GHSA-5hgr-hg42-57jg)
- <https://github.com/py-pdf/pypdf/security/advisories/GHSA-5hgr-hg42-57jg>
- <https://github.com/py-pdf/pypdf/pull/3806>
- <https://github.com/py-pdf/pypdf>
- <https://github.com/py-pdf/pypdf/releases/tag/6.12.2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-5hgr-hg42-57jg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-5hgr-hg42-57jg/>. Everything for agents: <https://agentprime.io/llms.txt>.