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CVE-2026-68477
ipvs: fix more places with wrong ipv6 transport offsets
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem net/netfilter. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-68477 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Sashiko reports for more incorrect IPv6 transport offsets. The app code for TCP was assuming IPv4 network header even after the ipvsh argument was provided. This can cause problems with apps over IPv6. As for the only official app in the kernel tree (FTP) this problem is harmless because we use Netfilter to mangle the FTP ports and we do not adjust the TCP seq numbers. Also, provide correct offset of the ICMPV6 header in ip_vs_out_icmp_v6() for correct checksum checks when the IPv6 packet has extension headers.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/netfilter/ipvs/ip_vs_app.c
net/netfilter/ipvs/ip_vs_core.c
- What this is
- IPVSMAINTAINERS section matched on net/netfilter/ipvs/ · netdev@vger.kernel.org · Maintained
- Kernel module
- ip_vs
Check it on the machine
grep -wE 'CONFIG_IP_VS|CONFIG_NETFILTER' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w ip_vsPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_IP_VS, CONFIG_NETFILTER
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.71%, higher than 52.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/netfilter
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.28 | 5.10.261 | 613ce63711b8 |
| 2.6.28 | 5.15.212 | 95d4511d81b2 |
| 2.6.28 | 6.1.178 | 3a9dc9b55b53 |
| 2.6.28 | 6.6.145 | a3f0d5b605cd |
| 2.6.28 | 6.12.97 | 7350eb7ead17 |
| 2.6.28 | 6.18.40 | d4ec18f48ce7 |
| 2.6.28 | 7.1.5 | 905d7a363ade |
| 2.6.28 | 7.2 | b3fe4cbd5838 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- The bug is triggered when remote IPv6 packets traverse IPVS netfilter hooks (NF_INET_LOCAL_IN/OUT/FORWARD) on an internet-facing load balancer; attackers send crafted IPv6 traffic with extension headers to a configured virtual service without local access.
- AC:LAttack complexity, low
- The attacker fully controls IPv6 extension headers and TCP/ICMPv6 packet contents on connections they initiate to the VIP; no race or privileged victim state is required beyond normal IPVS load-balancer operation.
- PR:NPrivileges required, none
- Exploitation requires only the ability to send network traffic to an IPVS-managed VIP; the attacker needs no account or capabilities on the target host (IPVS configuration is an environmental prerequisite, not attacker privilege).
- UI:NUser interaction, none
- No victim user interaction is required beyond the attacker sending malicious IPv6 packets over an established or new connection to the load-balanced service.
- S:UScope, unchanged
- Impact is confined to kernel memory corruption and packet handling within the load-balancer host; it does not cross a VM, container, or IOMMU security boundary.
- C:HConfidentiality impact, high
- Using ip_hdrlen() on IPv6 skbs reads TCP sequence/ack fields from the wrong skb offset (into the IPv6 header or extension-header area), constituting an out-of-bounds read exploitable for information disclosure.
- I:HIntegrity impact, high
- In ip_vs_out_icmp_v6, passing sizeof(ipv6hdr) instead of ipvsh->len causes ip_vs_nat_icmp_v6 to write ICMP/address/port fields at the wrong skb offset, corrupting extension headers or adjacent packet data.
- A:HAvailability impact, high
- Corrupting IPv6/ICMP/TCP header fields in the skb can cause kernel oops, panics, or connection disruption on the load balancer when malformed packets are processed or forwarded.