{"id":"CVE-2026-101307","aliases":["EUVD-2026-101882","GHSA-gpr4-gr7v-w9p3"],"status":"published","title":"Remotely triggerable buffer overflow in tcp_rack","description":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.\n\nA remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.00313,"percentile":0.24416,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-122","CWE-787"],"published":"2026-10-15T07:05:02Z","modified":"2026-10-20T00:31:55Z","products":[{"vendor":"freebsd","product":"freebsd"}],"references":[{"url":"https://security.freebsd.org/advisories/FreeBSD-SA-26:70.tcp.asc","tags":["vendor-advisory","Mitigation","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-101307"},{"url":"https://github.com/advisories/GHSA-gpr4-gr7v-w9p3"}],"sources":{"cve":[{"id":"CVE-2026-101307","title":"Remotely triggerable buffer overflow in tcp_rack","description":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.\n\nA remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.","status":"published","published":"2026-10-15T07:05:02.295Z","modified":"2026-10-15T16:48:11.023Z","cvss":[{"version":"4.0","score":8.2,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"adp"}],"cwes":["CWE-122","CWE-787"],"updated_at":"2026-11-02T14:20:10.143031Z"}],"euvd":[{"id":"EUVD-2026-101882","description":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.\n\nA remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.","status":"published","published":"2026-10-15T07:05:02Z","modified":"2026-10-15T16:48:11Z","cvss":[{"version":"4.0","score":8.2,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:00:11.901066Z"}],"ghsa":[{"id":"GHSA-gpr4-gr7v-w9p3","title":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter. ...","description":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.\n\nA remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.","status":"published","published":"2026-10-15T09:30:32Z","modified":"2026-10-20T00:31:55Z","cvss":[{"version":"4.0","score":8.2,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/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","level":"high"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical"}],"cwes":["CWE-122"],"updated_at":"2026-11-02T15:14:02.308554Z"}],"nvd":[{"id":"CVE-2026-101307","description":"When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.\n\nA remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.","status":"published","published":"2026-10-15T07:17:57.89Z","modified":"2026-10-20T00:21:51.247Z","cvss":[{"version":"4.0","score":8.2,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/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","level":"high","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-122","CWE-787"],"updated_at":"2026-11-02T14:12:59.328869Z"}]}}