{"api_version":"1","generated_at":"2026-07-23T19:19:34+00:00","cve":"CVE-2026-23472","urls":{"html":"https://cve.report/CVE-2026-23472","api":"https://cve.report/api/cve/CVE-2026-23472.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-23472","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-23472"},"summary":{"title":"serial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN\n\nuart_write_room() and uart_write() behave inconsistently when\nxmit_buf is NULL (which happens for PORT_UNKNOWN ports that were\nnever properly initialized):\n\n- uart_write_room() returns kfifo_avail() which can be > 0\n- uart_write() checks xmit_buf and returns 0 if NULL\n\nThis inconsistency causes an infinite loop in drivers that rely on\ntty_write_room() to determine if they can write:\n\n  while (tty_write_room(tty) > 0) {\n      written = tty->ops->write(...);\n      // written is always 0, loop never exits\n  }\n\nFor example, caif_serial's handle_tx() enters an infinite loop when\nused with PORT_UNKNOWN serial ports, causing system hangs.\n\nFix by making uart_write_room() also check xmit_buf and return 0 if\nit's NULL, consistent with uart_write().\n\nReproducer: https://gist.github.com/mrpre/d9a694cc0e19828ee3bc3b37983fde13","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-03 16:16:34","updated_at":"2026-07-20 20:10:00"},"problem_types":["CWE-835"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/bc70f2b36cf474d5cc8ecbcaf57f3e326fdec67c","name":"https://git.kernel.org/stable/c/bc70f2b36cf474d5cc8ecbcaf57f3e326fdec67c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/455ce986fa356ff43a43c0d363ba95fa152f21d5","name":"https://git.kernel.org/stable/c/455ce986fa356ff43a43c0d363ba95fa152f21d5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/efe85a557186b7fe915572ae93a8f3f78bfd9a22","name":"https://git.kernel.org/stable/c/efe85a557186b7fe915572ae93a8f3f78bfd9a22","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-23472","name":"CVE 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the Linux kernel, the following vulnerability has been resolved:\n\nserial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN\n\nuart_write_room() and uart_write() behave inconsistently when\nxmit_buf is NULL (which happens for PORT_UNKNOWN ports that were\nnever properly initialized):\n\n- uart_write_room() returns kfifo_avail() which can be > 0\n- uart_write() checks xmit_buf and returns 0 if NULL\n\nThis inconsistency causes an infinite loop in drivers that rely on\ntty_write_room() to determine if they can write:\n\n  while (tty_write_room(tty) > 0) {\n      written = tty->ops->write(...);\n      // written is always 0, loop never exits\n  }\n\nFor example, caif_serial's handle_tx() enters an infinite loop when\nused with PORT_UNKNOWN serial ports, causing system hangs.\n\nFix by making uart_write_room() also check xmit_buf and return 0 if\nit's NULL, consistent with uart_write().\n\nReproducer: https://gist.github.com/mrpre/d9a694cc0e19828ee3bc3b37983fde13"}],"providerMetadata":{"dateUpdated":"2026-05-11T22:07:41.736Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/efe85a557186b7fe915572ae93a8f3f78bfd9a22"},{"url":"https://git.kernel.org/stable/c/bc70f2b36cf474d5cc8ecbcaf57f3e326fdec67c"},{"url":"https://git.kernel.org/stable/c/455ce986fa356ff43a43c0d363ba95fa152f21d5"}],"title":"serial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-23472","datePublished":"2026-04-03T15:15:51.209Z","dateReserved":"2026-01-13T15:37:46.022Z","dateUpdated":"2026-05-11T22:07:41.736Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-03 16:16:34","lastModifiedDate":"2026-07-20 20:10:00","problem_types":["CWE-835"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12.1","versionEndExcluding":"6.18.20","matchCriteriaId":"C04EFB79-759E-465D-B79E-F062CD8CBD1B"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"6.19.10","matchCriteriaId":"96D34333-38BE-4414-9E79-6EB764329581"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*","matchCriteriaId":"6F62EECE-8FB1-4D57-85D8-CB9E23CF313C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*","matchCriteriaId":"4F76C298-81DC-43E4-8FC9-DC005A2116EF"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*","matchCriteriaId":"0AB349B2-3F78-4197-882B-90ADB3BF645A"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*","matchCriteriaId":"6AC88830-A9BC-4607-B572-A4B502FC9FD0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*","matchCriteriaId":"476CB3A5-D022-4F13-AAEF-CB6A5785516A"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*","matchCriteriaId":"F253B622-8837-4245-BCE5-A7BF8FC76A16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*","matchCriteriaId":"4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*","matchCriteriaId":"F666C8D8-6538-46D4-B318-87610DE64C34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*","matchCriteriaId":"02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"23472","Ordinal":"1","Title":"serial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN","CVE":"CVE-2026-23472","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"23472","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN\n\nuart_write_room() and uart_write() behave inconsistently when\nxmit_buf is NULL (which happens for PORT_UNKNOWN ports that were\nnever properly initialized):\n\n- uart_write_room() returns kfifo_avail() which can be > 0\n- uart_write() checks xmit_buf and returns 0 if NULL\n\nThis inconsistency causes an infinite loop in drivers that rely on\ntty_write_room() to determine if they can write:\n\n  while (tty_write_room(tty) > 0) {\n      written = tty->ops->write(...);\n      // written is always 0, loop never exits\n  }\n\nFor example, caif_serial's handle_tx() enters an infinite loop when\nused with PORT_UNKNOWN serial ports, causing system hangs.\n\nFix by making uart_write_room() also check xmit_buf and return 0 if\nit's NULL, consistent with uart_write().\n\nReproducer: https://gist.github.com/mrpre/d9a694cc0e19828ee3bc3b37983fde13","Type":"Description","Title":"serial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN"}]}}}