CVE-2023-4809
As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.80%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is. As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 0.80% probability · 55th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-167
- Affected
- freebsd/freebsd
- Source
- secteam@freebsd.org
References
- http://www.openwall.com/lists/oss-security/2023/09/08/5Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/09/08/6Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/09/08/7Mailing List, Third Party Advisory
- https://security.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascVendor Advisory
- https://security.netapp.com/advisory/ntap-20231221-0009/
- http://www.openwall.com/lists/oss-security/2023/09/08/5Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/09/08/6Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/09/08/7Mailing List, Third Party Advisory
- https://security.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascVendor Advisory
- https://security.netapp.com/advisory/ntap-20231221-0009/
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.