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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-101307

A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.

HIGH 8.2EPSS 0.31%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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. 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.

CVSS 4.0
8.2 HIGHCVSS: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/M
EPSS
0.31% probability · 24th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-122, CWE-787
Affected
freebsd/freebsd
Source
secteam@freebsd.org
EPSS trend
0%3%5%15 October 2026: 0.17%26 October 2026: 0.31%15 October 202626 October 2026

EPSS moved from 0.2% on 15 October 2026 to 0.3% on 26 October 2026.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.