PYSEC-2026-3616

Vulnerability from pysec - Published: 2026-08-04 11:34 - Updated: 2026-08-04 13:36
VLAI
Details

Summary

The regular expression used to parse the convolution filter exhibits exponential-time backtracking for certain inputs, enabling a Regular Expression Denial of Service (ReDoS).

Details

The RegExp for convolution is defined as convolution\((?:\s*((?:[-]?[\d]+\.?[\d]*[;])*(?:[-]?[\d]+\.?[\d]*))\s*)(?:,\s*([\d]+)\s*)(?:,\s*([Tt]rue|[Ff]alse|1|0)\s*)?\). Within this expression a dangerous subpattern effectively behaves like (\d+)*,\d+.

PoC

A filter string containing many repeated values will exhaust re.match: - convolution(-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11) - http://localhost:8888/unsafe/0x0/smart/filters:convolution(-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11)/x.png

The evaluation occurs on https://github.com/thumbor/thumbor/blob/master/thumbor/filters/init.py#L189.

Impact

A specially crafted URL will lead to denial of service, as new images won't be processed until re.match returns.

Impacted products
Name purl
thumbor pkg:pypi/thumbor

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "thumbor",
        "purl": "pkg:pypi/thumbor"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.8.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.3",
        "4.10.0",
        "4.10.1",
        "4.10.2",
        "4.10.3",
        "4.11.0",
        "4.11.1",
        "4.12.0",
        "4.12.1",
        "4.12.2",
        "4.4.1",
        "4.5.3",
        "4.5.4",
        "4.6.0",
        "4.7.0",
        "4.7.1",
        "4.8.0",
        "4.8.1",
        "4.8.2",
        "4.8.3",
        "4.8.4",
        "4.8.5",
        "4.8.6",
        "4.9.0",
        "4.9.1",
        "5.0.0",
        "5.0.0rc1",
        "5.0.0rc2",
        "5.0.1",
        "5.0.2",
        "5.0.3",
        "5.0.4",
        "5.0.5",
        "5.0.6",
        "5.1.0",
        "5.2.0",
        "5.2.1",
        "6.0.0",
        "6.0.0b1",
        "6.0.0b2",
        "6.0.0b3",
        "6.0.0b4",
        "6.0.0b5",
        "6.0.1",
        "6.0.2",
        "6.1.0",
        "6.1.1",
        "6.1.2",
        "6.1.3",
        "6.1.4",
        "6.1.5",
        "6.2.0",
        "6.2.1",
        "6.3.0",
        "6.3.1",
        "6.3.2",
        "6.4.0",
        "6.4.1",
        "6.4.2",
        "6.4.3",
        "6.5.0",
        "6.5.1",
        "6.5.2",
        "6.6.0",
        "6.6.1",
        "6.7.0",
        "6.7.1",
        "6.7.2",
        "6.7.3",
        "6.7.4",
        "6.7.5",
        "6.7.6",
        "7.0.0",
        "7.0.0a1",
        "7.0.0a2",
        "7.0.0a3",
        "7.0.0a4",
        "7.0.0a5",
        "7.0.0b1",
        "7.0.1",
        "7.0.10",
        "7.0.11",
        "7.0.12",
        "7.0.2",
        "7.0.3",
        "7.0.5",
        "7.0.6",
        "7.0.7",
        "7.0.8",
        "7.0.9",
        "7.1.0",
        "7.1.1",
        "7.1.2",
        "7.2.0",
        "7.2.1",
        "7.3.0",
        "7.3.1",
        "7.3.2",
        "7.4.0",
        "7.4.1",
        "7.4.2",
        "7.4.3",
        "7.4.4",
        "7.4.5",
        "7.4.6",
        "7.4.7",
        "7.5.0",
        "7.5.1",
        "7.5.2",
        "7.6.0",
        "7.7.0",
        "7.7.1",
        "7.7.2",
        "7.7.3",
        "7.7.4",
        "7.7.5",
        "7.7.6",
        "7.7.7"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53504",
    "GHSA-5vjc-7cxw-4w6j"
  ],
  "details": "### Summary\nThe regular expression used to parse the `convolution` filter exhibits exponential-time backtracking for certain inputs, enabling a Regular Expression Denial of Service (ReDoS).\n\n### Details\nThe RegExp for `convolution` is defined as `convolution\\((?:\\s*((?:[-]?[\\d]+\\.?[\\d]*[;])*(?:[-]?[\\d]+\\.?[\\d]*))\\s*)(?:,\\s*([\\d]+)\\s*)(?:,\\s*([Tt]rue|[Ff]alse|1|0)\\s*)?\\)`. Within this expression a dangerous subpattern effectively behaves like `(\\d+)*,\\d+`.\n\n### PoC\nA filter string containing many repeated values will exhaust `re.match`:\n- `convolution(-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11)`\n- http://localhost:8888/unsafe/0x0/smart/filters:convolution(-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11;-11)/x.png\n\nThe evaluation occurs on https://github.com/thumbor/thumbor/blob/master/thumbor/filters/__init__.py#L189.\n\n### Impact\nA specially crafted URL will lead to denial of service, as new images won\u0027t be processed until `re.match` returns.",
  "id": "PYSEC-2026-3616",
  "modified": "2026-08-04T13:36:37.885545Z",
  "published": "2026-08-04T11:34:46.398484Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thumbor/thumbor/security/advisories/GHSA-5vjc-7cxw-4w6j"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thumbor/thumbor/commit/3f38fe1610d20168e91f76d432212de30727eb2e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thumbor/thumbor"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thumbor/thumbor/releases/tag/7.8.0"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/thumbor"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-5vjc-7cxw-4w6j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53504"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Thumbor has Regex Denial of Service (ReDoS) in `convolution` filter"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…

Loading…