High Memory corruption

CVE-2026-101307 — Remotely triggerable buffer overflow in tcp_rack

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. A 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.

Published Oct 15, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: freebsd

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Freebsd

CVSS base

8.2

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Freebsd Freebsd).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Freebsd	Freebsd	≥ 15.1-RELEASE and < p5	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Attack requirements

Present

Privileges required

None

User interaction

None

Scope

Confidentiality (vulnerable system)

None

Integrity (vulnerable system)

None

Availability (vulnerable system)

High

Confidentiality (subsequent)

None

Integrity (subsequent)

None

Availability (subsequent)

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.2	CVSS 4.0	High	—	—	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
8.2	CVSS 4.0	High	—	—	CISA-ADP via CVE Program (cve.org) e CISA ADP

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

(score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-122 · Heap-based Buffer Overflow

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
CVSS changed · 6.5 → 8.2
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · Awaiting Analysis → Undergoing Analysis
Oct 15, 2026 · NIST National Vulnerability Database
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
CVSS changed · 6.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · Received → Awaiting Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record published
Oct 15, 2026
Affected products added · freebsd/freebsd
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · Alertas do Telegram
CVE published
Oct 15, 2026 · freebsd

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

security.freebsd.org/advisories/FreeBSD-SA-26:70.tcp.asc
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Freebsd
every CVE for this vendor

Memory corruption
same class

CWE-122
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-101311 Multiple vulnerabilities in bhyve device models 11h
High CVE-2026-101310 Multiple vulnerabilities in bhyve device models 11h
High CVE-2026-101309 Multiple vulnerabilities in bhyve device models 11h
Unknown CVE-2026-58099 Memory safety bugs in kqueue copy-on-fork implementation 12h
Unknown CVE-2026-58098 Heap out-of-bounds access in semop(2) 12h
Unknown CVE-2026-58100 Memory safety bugs in kqueue copy-on-fork implementation 12h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-101307 is "Remotely triggerable buffer overflow in tcp_rack", rated High. It affects Freebsd (Freebsd); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.2 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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