Vulnerability-Lookup

UBUNTU-CVE-2026-29078 (CVE-2026-29078)

Vulnerability from osv_ubuntu – Published: 2026-03-13 19:54 – Updated: 2026-05-20 15:26 – Source website

Details

Lexbor is a web browser engine library. Prior to 2.7.0, the ISO‑2022‑JP encoder in Lexbor fails to reset the temporary size variable between iterations. The statement ctx->buffer_used -= size with a stale size = 3 causes an integer underflow that wraps to SIZE_MAX. Afterwards, memcpy is called with a negative length, leading to an out‑of‑bounds read from the stack and an out‑of‑bounds write to the heap. The source data is partially controllable via the contents of the DOM tree. This vulnerability is fixed in 2.7.0.

Severity

8.2 (High)


                    
                      CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

7.5 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-29078	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-29078	REPORT
	https://github.com/lexbor/lexbor/security/advisor…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblexbor2",
            "binary_version": "2.6.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "lexbor",
        "purl": "pkg:deb/ubuntu/lexbor@2.6.0-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "Lexbor is a web browser engine library. Prior to 2.7.0, the ISO\u20112022\u2011JP encoder in Lexbor fails to reset the temporary size variable between iterations. The statement ctx-\u003ebuffer_used -= size with a stale size = 3 causes an integer underflow that wraps to SIZE_MAX. Afterwards, memcpy is called with a negative length, leading to an out\u2011of\u2011bounds read from the stack and an out\u2011of\u2011bounds write to the heap. The source data is partially controllable via the contents of the DOM tree. This vulnerability is fixed in 2.7.0.",
  "id": "UBUNTU-CVE-2026-29078",
  "modified": "2026-05-20T15:26:08Z",
  "published": "2026-03-13T19:54:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-29078"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-29078"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lexbor/lexbor/security/advisories/GHSA-mrwr-xh7f-96v3"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-29078"
  ]
}

CVE-2026-29078 (GCVE-0-2026-29078)

Vulnerability from cvelistv5 – Published: 2026-03-13 17:18 – Updated: 2026-03-16 17:05

Title

Integer Underflow in Lexbor ISO‑2022‑JP Encoder

Summary

Severity

8.2 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-16 17:05 UTC

CWE

CWE-191 - Integer Underflow (Wrap or Wraparound)
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root Scorecard

References

1 reference

URL	Tags
https://github.com/lexbor/lexbor/security/advisor…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
lexbor	lexbor	Affected: < 2.7.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-29078",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-16T17:05:45.395180Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-16T17:05:52.178Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "lexbor",
          "vendor": "lexbor",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.7.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Lexbor is a web browser engine library. Prior to 2.7.0, the ISO\u20112022\u2011JP encoder in Lexbor fails to reset the temporary size variable between iterations. The statement ctx-\u003ebuffer_used -= size with a stale size = 3 causes an integer underflow that wraps to SIZE_MAX. Afterwards, memcpy is called with a negative length, leading to an out\u2011of\u2011bounds read from the stack and an out\u2011of\u2011bounds write to the heap. The source data is partially controllable via the contents of the DOM tree. This vulnerability is fixed in 2.7.0."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-191",
              "description": "CWE-191: Integer Underflow (Wrap or Wraparound)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787: Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-13T17:18:47.646Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/lexbor/lexbor/security/advisories/GHSA-mrwr-xh7f-96v3",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/lexbor/lexbor/security/advisories/GHSA-mrwr-xh7f-96v3"
        }
      ],
      "source": {
        "advisory": "GHSA-mrwr-xh7f-96v3",
        "discovery": "UNKNOWN"
      },
      "title": "Integer Underflow in Lexbor ISO\u20112022\u2011JP Encoder"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-29078",
    "datePublished": "2026-03-13T17:18:47.646Z",
    "dateReserved": "2026-03-03T20:51:43.483Z",
    "dateUpdated": "2026-03-16T17:05:52.178Z",
    "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.

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.

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UBUNTU-CVE-2026-29078 (CVE-2026-29078)

CVE-2026-29078 (GCVE-0-2026-29078)

Tags

Sightings

Nomenclature

Related by attack behaviour