Vulnerability-Lookup

ubuntu-cve-2026-53501

Vulnerability from osv_ubuntu

Published

2026-07-31 19:17

Modified

2026-08-06 00:20

Summary

Details

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor’s HMAC validation can be bypassed due to the use of Python’s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0.

Severity

8.2 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-53501	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-53501	REPORT
	https://github.com/thumbor/thumbor/security/advis…	REPORT
	https://github.com/thumbor/thumbor/commit/e3ae3e2…	REPORT
	https://github.com/thumbor/thumbor/releases/tag/7.8.0	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "thumbor",
            "binary_version": "7.7.7-5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "thumbor",
        "purl": "pkg:deb/ubuntu/thumbor@7.7.7-5?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.7.7-4",
        "7.7.7-5"
      ]
    }
  ],
  "aliases": [],
  "details": "Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor\u2019s HMAC validation can be bypassed due to the use of Python\u2019s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0.",
  "id": "UBUNTU-CVE-2026-53501",
  "modified": "2026-08-06T00:20:53Z",
  "published": "2026-07-31T19:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-53501"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-53501"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/thumbor/thumbor/releases/tag/7.8.0"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-53501"
  ]
}

CVE-2026-53501 (GCVE-0-2026-53501)

Vulnerability from cvelistv5 – Published: 2026-07-31 18:42 – Updated: 2026-07-31 19:58

Title

Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signature

Summary

Severity

8.2 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-31 19:57 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/thumbor/thumbor/security/advis…	x_refsource_CONFIRM
https://github.com/thumbor/thumbor/commit/e3ae3e2…	x_refsource_MISC
https://github.com/thumbor/thumbor/releases/tag/7.8.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
thumbor	thumbor	Affected: < 7.8.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-53501",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-31T19:57:48.500225Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-31T19:58:01.891Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "thumbor",
          "vendor": "thumbor",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 7.8.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor\u2019s HMAC validation can be bypassed due to the use of Python\u2019s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347: Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-31T18:42:42.360Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9"
        },
        {
          "name": "https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b"
        },
        {
          "name": "https://github.com/thumbor/thumbor/releases/tag/7.8.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/thumbor/thumbor/releases/tag/7.8.0"
        }
      ],
      "source": {
        "advisory": "GHSA-mw3h-qjxj-6xg9",
        "discovery": "UNKNOWN"
      },
      "title": "Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signature"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53501",
    "datePublished": "2026-07-31T18:42:42.360Z",
    "dateReserved": "2026-06-09T17:05:25.059Z",
    "dateUpdated": "2026-07-31T19:58:01.891Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.