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CVE-2023-6534

TCP spoofing vulnerability in pf(4)

HIGH
7.5
CVSS Score
Published: December 13, 2023 at 08:12 AM UTC
Updated: June 17, 2026 at 06:50 AM UTC
1 product affected across 1 vendorFreeBSD

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Severity
HIGH7.5
Exploit prediction
EPSS 0.7%

Description

In versions of FreeBSD 14.0-RELEASE before 14-RELEASE-p2, FreeBSD 13.2-RELEASE before 13.2-RELEASE-p7 and FreeBSD 12.4-RELEASE before 12.4-RELEASE-p9, the pf(4) packet filter incorrectly validates TCP sequence numbers.  This could allow a malicious actor to execute a denial-of-service attack against hosts behind the firewall.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

FreeBSD· Freebsd
95%
12.4-RELEASE ≤ v < p913.2-RELEASE ≤ v < p714.0-RELEASE ≤ v < p212.412.4 p112.4 p212.4 p312.4 p412.4 p512.4 p612.4 p712.4 p812.4 rc2-p112.4 rc2-p212.4-RELEASE13.213.2 p113.2 p213.2 p313.2 p413.2 p513.2 p613.2-RELEASE14.014.0 beta514.0 p114.0 rc314.0 rc4-p114.0-RELEASE
Affected range stops below p2, so it looks safe — our inference, not a vendor statement
Affected range stops below p7, so it looks safe — our inference, not a vendor statement
Affected range stops below p9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

Vendor Advisory
Source: [email protected]
https://security.freebsd.org/advisories/FreeBSD-SA-23:17.pf.asc
Source: [email protected]
https://security.netapp.com/advisory/ntap-20240112-0007/

CVSS

7.5HIGH[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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