PYSEC-2026-3019

Vulnerability from pysec - Published: 2026-07-13 14:36 - Updated: 2026-07-13 16:06
VLAI
Details

Impact

An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing a content stream with a rather large /Length value, regardless of the actual data length inside the stream.

Patches

This has been fixed in pypdf==6.8.0.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #3675.

As far as we are aware, this mostly affects reading from buffers of unknown size, as returned by open("file.pdf", mode="rb") for example. Passing a file path or a BytesIO buffer to pypdf instead does not seem to trigger the vulnerability.

Severity
6.8 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Impacted products
Name purl
pypdf pkg:pypi/pypdf
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pypdf",
        "purl": "pkg:pypi/pypdf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.8.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0",
        "1.1",
        "1.10",
        "1.11",
        "1.12",
        "1.13",
        "1.2",
        "1.3",
        "1.4",
        "1.5",
        "1.6",
        "1.7",
        "1.8",
        "1.9",
        "3.1.0",
        "3.10.0",
        "3.11.0",
        "3.11.1",
        "3.12.0",
        "3.12.1",
        "3.12.2",
        "3.13.0",
        "3.14.0",
        "3.15.0",
        "3.15.1",
        "3.15.2",
        "3.15.3",
        "3.15.4",
        "3.15.5",
        "3.16.0",
        "3.16.1",
        "3.16.2",
        "3.16.3",
        "3.16.4",
        "3.17.0",
        "3.17.1",
        "3.17.2",
        "3.17.3",
        "3.17.4",
        "3.2.0",
        "3.2.1",
        "3.3.0",
        "3.4.0",
        "3.4.1",
        "3.5.0",
        "3.5.1",
        "3.5.2",
        "3.6.0",
        "3.7.0",
        "3.7.1",
        "3.8.0",
        "3.8.1",
        "3.9.0",
        "3.9.1",
        "4.0.0",
        "4.0.1",
        "4.0.2",
        "4.1.0",
        "4.2.0",
        "4.3.0",
        "4.3.1",
        "5.0.0",
        "5.0.1",
        "5.1.0",
        "5.2.0",
        "5.3.0",
        "5.3.1",
        "5.4.0",
        "5.5.0",
        "5.6.0",
        "5.6.1",
        "5.7.0",
        "5.8.0",
        "5.9.0",
        "6.0.0",
        "6.1.0",
        "6.1.1",
        "6.1.2",
        "6.1.3",
        "6.2.0",
        "6.3.0",
        "6.4.0",
        "6.4.1",
        "6.4.2",
        "6.5.0",
        "6.6.0",
        "6.6.1",
        "6.6.2",
        "6.7.0",
        "6.7.1",
        "6.7.2",
        "6.7.3",
        "6.7.4",
        "6.7.5"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-31826",
    "GHSA-hqmh-ppp3-xvm7"
  ],
  "details": "### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing a content stream with a rather large `/Length` value, regardless of the actual data length inside the stream.\n\n### Patches\nThis has been fixed in [pypdf==6.8.0](https://github.com/py-pdf/pypdf/releases/tag/6.8.0).\n\n### Workarounds\nIf you cannot upgrade yet, consider applying the changes from PR [#3675](https://github.com/py-pdf/pypdf/pull/3675).\n\nAs far as we are aware, this mostly affects reading from buffers of unknown size, as returned by `open(\"file.pdf\", mode=\"rb\")` for example. Passing a file path or a `BytesIO` buffer to *pypdf* instead does not seem to trigger the vulnerability.",
  "id": "PYSEC-2026-3019",
  "modified": "2026-07-13T16:06:01.898543Z",
  "published": "2026-07-13T14:36:42.160674Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/py-pdf/pypdf/security/advisories/GHSA-hqmh-ppp3-xvm7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31826"
    },
    {
      "type": "WEB",
      "url": "https://github.com/py-pdf/pypdf/pull/3675"
    },
    {
      "type": "WEB",
      "url": "https://github.com/py-pdf/pypdf/commit/3c550b3196adeba1506a26e57c09c09fac75e9aa"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/py-pdf/pypdf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/py-pdf/pypdf/releases/tag/6.8.0"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/pypdf"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-hqmh-ppp3-xvm7"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "pypdf: manipulated stream length values can exhaust RAM"
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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