{"id":"CVE-2026-49840","state":"PUBLISHED","title":"FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing","description":"FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to version 1.11.1, esl_recv_event() parses Content-Length with atol() and passes the result straight to malloc(len + 1) with no sign or magnitude check. A malicious or man-in-the-middle ESL peer can send a frame with a negative Content-Length to corrupt the heap of, or crash, any process linked against libesl, before the client has authenticated to that peer. This issue has been patched in version 1.11.1.","publishedAt":"2026-06-09T16:00:56.687Z","updatedAt":"2026-06-09T17:00:21.313Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["signalwire freeswitch"],"affected":[{"vendor":"signalwire","product":"freeswitch","versions":[{"version":"< 1.11.1","status":"affected"}]}],"references":["https://github.com/signalwire/freeswitch/security/advisories/GHSA-g597-9fgg-ghg9","https://github.com/signalwire/freeswitch/releases/tag/v1.11.1"],"weaknesses":["CWE-20","CWE-122","CWE-195","CWE-787"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/49xxx/CVE-2026-49840.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-49840","state":"PUBLISHED","datePublished":"2026-06-09T16:00:56.687Z","dateUpdated":"2026-06-09T17:00:21.313Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-01T18:50:36.056Z"},"containers":{"cna":{"title":"FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing","descriptions":[{"lang":"en","value":"FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to version 1.11.1, esl_recv_event() parses Content-Length with atol() and passes the result straight to malloc(len + 1) with no sign or magnitude check. A malicious or man-in-the-middle ESL peer can send a frame with a negative Content-Length to corrupt the heap of, or crash, any process linked against libesl, before the client has authenticated to that peer. This issue has been patched in version 1.11.1."}],"affected":[{"vendor":"signalwire","product":"freeswitch","versions":[{"version":"< 1.11.1","status":"affected"}]}],"references":[{"url":"https://github.com/signalwire/freeswitch/security/advisories/GHSA-g597-9fgg-ghg9","name":"https://github.com/signalwire/freeswitch/security/advisories/GHSA-g597-9fgg-ghg9","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/signalwire/freeswitch/releases/tag/v1.11.1","name":"https://github.com/signalwire/freeswitch/releases/tag/v1.11.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":9.1,"baseSeverity":"CRITICAL","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:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"CWE-20: Improper Input Validation","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-122","lang":"en","description":"CWE-122: Heap-based Buffer Overflow","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-195","lang":"en","description":"CWE-195: Signed to Unsigned Conversion Error","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-09T16:00:56.687Z"},"source":{"advisory":"GHSA-g597-9fgg-ghg9","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-09T16:59:32.826404Z","id":"CVE-2026-49840","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-09T17:00:21.313Z"}}]}}}