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CVE-2021-47249

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: net: rds: fix memory leak in rds_recvmsg Syzbot reported memory leak in rds.

Published May 21, 2024CWE-401EPSS 0.24%

Overview

CVE-2021-47249 is a medium-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: rds: fix memory leak in rds_recvmsg

Syzbot reported memory leak in rds. The problem

was in unputted refcount in case of error.

int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,

int msg_flags)

{

...

if (!rds_next_incoming(rs, &inc)) {

...

}

After this "if" inc refcount incremented and

if (rds_cmsg_recv(inc, msg, rs)) {

ret = -EFAULT;

goto out;

}

...

out:

return ret;

}

in case of rds_cmsg_recv() fail the refcount won't be

decremented. And it's easy to see from ftrace log, that

rds_inc_addref() don't have rds_inc_put() pair in

rds_recvmsg() after rds_cmsg_recv()

1) | rds_recvmsg() {

1) 3.721 us | rds_inc_addref();

1) 3.853 us | rds_message_inc_copy_to_user();

1) + 10.395 us | rds_cmsg_recv();

1) + 34.260 us | }

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/06b7cb0194bd1ede0dd27f3a946e7c0279fba44aRefgit.kernel.org/stable/c/1f79bc8ae81c05eb112a53f981cb2c244ee50d02Refgit.kernel.org/stable/c/2038cd15eacdf7512755c27686822e0052eb9042Refgit.kernel.org/stable/c/423c6939758fb3b9cf5abbd1e7792068a5c4ae8cRefgit.kernel.org/stable/c/49bfcbfd989a8f1f23e705759a6bb099de2cff9fRefgit.kernel.org/stable/c/5946fbf48355f5a8caeff72580c7658da5966b86Refgit.kernel.org/stable/c/8c3ec88b03e9e4ca117dcdc4204fd3edcd02084fRefgit.kernel.org/stable/c/b25b60d076164edb3025e85aabd2cf50a5215b91Refgit.kernel.org/stable/c/06b7cb0194bd1ede0dd27f3a946e7c0279fba44aRefgit.kernel.org/stable/c/1f79bc8ae81c05eb112a53f981cb2c244ee50d02

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47249?

CVE-2021-47249 is a medium-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47249?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47249?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47249?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47249 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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