CVE Explorer
CVE-2026-4247
When a challenge ACK is to be sent tcp_respond() constructs and sends the challenge ACK and consumes the mbuf that is passed in. When no challenge ACK should be sent the function returns and leaks the mbuf.
If an attacker is either on path with an established TCP connection, or can themselves establish a TCP connection, to an affected FreeBSD machine, they can easily craft and send packets which meet the challenge ACK criteria and cause the FreeBSD host to leak an mbuf for each crafted packet
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unknown","modules":["tcp"],"product":"FreeBSD","vendor":"FreeBSD","versions":[{"lessThan":"p5","status":"affected","version":"15.0-RELEASE","versionType":"release"},{"lessThan":"p1","status":"affected","version":"14.4-RELEASE","versionType":"release"},{"lessThan":"p10","status":"affected","version":"14.3-RELEASE","versionType":"release"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:8b2dd70b9669b2eeefcf9c1084c3f70927e1bb86c13faa5617fa2e15980e6786 · sha256:1ff523c4f16c3211… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:8b2dd70b9669b2eeefcf9c1084c3f70927e1bb86c13faa5617fa2e15980e6786 · sha256:1ff523c4f16c3211… · /containers/adp/0/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-401","description":"CWE-401: Missing Release of Memory after Effective Lifetime","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:8b2dd70b9669b2eeefcf9c1084c3f70927e1bb86c13faa5617fa2e15980e6786 · sha256:1ff523c4f16c3211… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"tags":["vendor-advisory"],"url":"https://security.freebsd.org/advisories/FreeBSD-SA-26:06.tcp.asc"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8b2dd70b9669b2eeefcf9c1084c3f70927e1bb86c13faa5617fa2e15980e6786 · sha256:1ff523c4f16c3211… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.