CVE-2026-63476

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{"affected": [{"affectedData": [{"product": "isomorphic-git", "vendor": "isomorphic-git", "versions": [{"status": "affected", "version": "< 1.38.6"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git reads a server-controlled targetSize while applying a packfile delta in src/utils/applyDelta.js and passes it without a bound to Buffer.alloc(targetSize). A malicious or man-in-the-middle-controlled remote can send one delta header that causes git.clone() or git.fetch() to allocate approximately 2 GB before validating the actual delta output. GitPackIndex.fromPack swallows the later size-mismatch error, so a host with sufficient memory may retain the resource waste without a visible failure, while containers, serverless functions, and small virtual machines may terminate. Node.js heap limits do not mitigate the off-heap Buffer allocation. This issue is fixed in version 1.38.6."}], "id": "CVE-2026-63476", "lastModified": "2026-11-07T04:17:32.990", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-63476", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-11-07T03:27:18.874587Z", "version": "2.0.3"}}]}, "published": "2026-11-03T20:18:16.063", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/pull/2370"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-789"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "isomorphic-git: isomorphic-git: Denial of Service via unbounded memory allocation during packfile processing", "id": "2566189", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2566189"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "status": "draft"}, "cwe": "CWE-770", "details": ["A flaw was found in isomorphic-git. A malicious or compromised remote Git server can cause a Denial of Service (DoS) by sending a specially crafted packfile delta header with an excessively large target size during clone or fetch operations. Because isomorphic-git allocates memory for the target size without proper bounds checking, this issue leads to excessive memory consumption and can crash applications running in memory-constrained environments, such as containers or serverless functions."], "name": "CVE-2026-63476", "package_state": [{"cpe": "cpe:/a:redhat:serverless:1", "fix_state": "Fix deferred", "package_name": "openshift-serverless-1/logic-rhel9-operator", "product_name": "OpenShift Serverless"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Fix deferred", "package_name": "rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend", "product_name": "Red Hat Developer Hub 1"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Fix deferred", "package_name": "rhdh/red-hat-developer-hub-backstage-plugin-scaffolder-backend-module-orchestrator", "product_name": "Red Hat Developer Hub 1"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Fix deferred", "package_name": "rhdh/rhdh-hub-rhel9", "product_name": "Red Hat Developer Hub 1"}, {"cpe": "cpe:/a:redhat:ansible_portal:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform/automation-portal", "product_name": "Self-service automation portal 2"}, {"cpe": "cpe:/a:redhat:ansible_portal:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform/bootc-automation-portal-rhel9", "product_name": "Self-service automation portal 2"}], "public_date": "2026-11-03T19:44:06Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63476\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63476\nhttps://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b\nhttps://github.com/isomorphic-git/isomorphic-git/pull/2370\nhttps://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6\nhttps://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.38.6)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "isomorphic-git", "source": "cna", "vendor": "isomorphic-git"}, "product": "isomorphic-git", "vendor": "isomorphic-git"}], "created": "2026-11-04T00:30:06.368409+00:00", "updated": "2026-11-04T10:15:12.053507+00:00", "vendors": ["isomorphic-git", "isomorphic-git$PRODUCT$isomorphic-git"]}