CVE-2024-27414 rtnetlink: fix error logic of IFLA_BRIDGE_FLAGS writing back
A logic error in the Linux kernel's rtnetlink bridge handling allows overflow writes, potentially enabling code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-27414?
CVE-2024-27414 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 17 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
rtnetlink: fix error logic of IFLA_BRIDGE_FLAGS writing back
In the commit d73ef2d69c0d ("rtnetlink: let rtnl_bridge_setlink checks IFLA_BRIDGE_MODE length"), an adjustment was made to the old loop logic in the function `rtnl_bridge_setlink` to enable the loop to also check the length of the IFLA_BRIDGE_MODE attribute. However, this adjustment removed the `break` statement and led to an error logic of the flags writing back at the end of this function.
if (have_flags) memcpy(nla_data(attr), &flags, sizeof(flags)); // attr should point to IFLA_BRIDGE_FLAGS NLA !!!
Before the mentioned commit, the `attr` is granted to be IFLA_BRIDGE_FLAGS. However, this is not necessarily true fow now as the updated loop will let the attr point to the last NLA, even an invalid NLA which could cause overflow writes.
This patch introduces a new variable `br_flag` to save the NLA pointer that points to IFLA_BRIDGE_FLAGS and uses it to resolve the mentioned error logic.
Which versions are affected by CVE-2024-27414?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-27414?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2024-27414 being exploited?
There is no known exploitation of CVE-2024-27414 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-27414, DEBIAN-CVE-2024-27414, GHSA-h9q8-5vjp-c6cg, UBUNTU-CVE-2024-27414.