CVE-2026-29008

{"id": "CVE-2026-29008", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-29008", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-09T13:55:52.553728Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"repo": "https://github.com/u-boot/u-boot", "vendor": "u-boot", "product": "u-boot", "versions": [{"status": "affected", "version": "0", "versionType": "custom", "lessThanOrEqual": "2026.04-rc3"}], "packageURL": "pkg:github/u-boot/u-boot", "defaultStatus": "affected"}]}], "published": "2026-07-08T17:17:21.047", "references": [{"url": "https://lists.denx.de/pipermail/u-boot/2026-May/617853.html", "tags": ["Mailing List", "Third Party Advisory"], "source": "disclosure@vulncheck.com"}, {"url": "https://u-boot.org/", "tags": ["Product"], "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/u-boot-rc3-integer-underflow-dos-via-tcp-rx-state-machine", "tags": ["Third Party Advisory", "Exploit"], "source": "disclosure@vulncheck.com"}, {"url": "https://y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/", "tags": ["Third Party Advisory", "Exploit"], "source": "disclosure@vulncheck.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-191"}]}], "descriptions": [{"lang": "en", "value": "U-Boot through 2026.04-rc3 contains an integer underflow vulnerability in the tcp_rx_state_machine() function (net/tcp.c) that allows a network-adjacent attacker to crash the bootloader by sending a malformed TCP SYN+ACK packet with a manipulated data offset field causing payload_len to become negative. When the TCP_SYN_SENT handler calls tcp_rx_user_data() without invoking tcp_seg_in_wnd() validation, the negative payload_len is implicitly converted to a large unsigned integer (e.g., 0xFFFFFFD8) and passed to memcpy() in store_block(), causing an immediate crash that prevents device boot and may enable memory corruption when CONFIG_LMB is disabled."}], "lastModified": "2026-07-22T18:32:12.677", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:denx:u-boot:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "097D2949-BA7E-411B-81C1-7AADF57C4849", "versionEndExcluding": "2026.04"}, {"criteria": "cpe:2.3:a:denx:u-boot:2026.04:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "39D97BA6-0B7B-4633-971E-3C79C58A57A5"}, {"criteria": "cpe:2.3:a:denx:u-boot:2026.04:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "94B93B6C-02D1-42C9-B862-C945511A0297"}, {"criteria": "cpe:2.3:a:denx:u-boot:2026.04:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "86FAEAE1-FCD8-426D-9452-E1885014C9A9"}], "operator": "OR"}]}], "sourceIdentifier": "disclosure@vulncheck.com"}