CVE-2021-47482

MEDIUM
Published May 22, 2024 Modified Apr 2, 2025 CWE-544

Description

In the Linux kernel, the following vulnerability has been resolved: net: batman-adv: fix error handling Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was in wrong error handling in batadv_mesh_init(). Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case of any batadv_*_init() calls failure. This approach may work well, when there is some kind of indicator, which can tell which parts of batadv are initialized; but there isn't any. All written above lead to cleaning up uninitialized fields. Even if we hide ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1] To fix these bugs we can unwind batadv_*_init() calls one by one. It is good approach for 2 reasons: 1) It fixes bugs on error handling path 2) It improves the performance, since we won't call unneeded batadv_*_free() functions. So, this patch makes all batadv_*_init() clean up all allocated memory before returning with an error to no call correspoing batadv_*_free() and open-codes batadv_mesh_free() with proper order to avoid touching uninitialized fields.

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CVSS v3.1 Score

5.3
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-544 CWE-544

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20 https://git.kernel.org/stable/c/0c6b199f09be489c48622537a550787fc80aea73 https://git.kernel.org/stable/c/6422e8471890273994fe8cc6d452b0dcd2c9483e https://git.kernel.org/stable/c/6f68cd634856f8ca93bafd623ba5357e0f648c68 https://git.kernel.org/stable/c/a8f7359259dd5923adc6129284fdad12fc5db347 https://git.kernel.org/stable/c/b0a2cd38553c77928ef1646ed1518486b1e70ae8 https://git.kernel.org/stable/c/e50f957652190b5a88a8ebce7e5ab14ebd0d3f00 https://git.kernel.org/stable/c/fbf150b16a3635634b7dfb7f229d8fcd643c6c51 https://git.kernel.org/stable/c/07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20 https://git.kernel.org/stable/c/0c6b199f09be489c48622537a550787fc80aea73 https://git.kernel.org/stable/c/6422e8471890273994fe8cc6d452b0dcd2c9483e https://git.kernel.org/stable/c/6f68cd634856f8ca93bafd623ba5357e0f648c68 https://git.kernel.org/stable/c/a8f7359259dd5923adc6129284fdad12fc5db347 https://git.kernel.org/stable/c/b0a2cd38553c77928ef1646ed1518486b1e70ae8 https://git.kernel.org/stable/c/e50f957652190b5a88a8ebce7e5ab14ebd0d3f00 https://git.kernel.org/stable/c/fbf150b16a3635634b7dfb7f229d8fcd643c6c51

Frequently Asked Questions

What is CVE-2021-47482? +
In the Linux kernel, the following vulnerability has been resolved: net: batman-adv: fix error handling Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was in wrong error handling in batadv_mesh_init(). Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case of any batadv_*_init() calls failure. This approach may work well, when there is some kind of indicator, which can tell which parts of batadv are initialized; but there isn't any. All written above lead to cleaning up uninitialized fields. Even if we hide ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1] To fix these bugs we can unwind batadv_*_init() calls one by one. It is good approach for 2 reasons: 1) It fixes bugs on error handling path 2) It improves the performance, since we won't call unneeded batadv_*_free() functions. So, this patch makes all batadv_*_init() clean up all allocated memory before returning with an error to no call correspoing batadv_*_free() and open-codes batadv_mesh_free() with proper order to avoid touching uninitialized fields. It has a CVSS v3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2021-47482? +
CVE-2021-47482 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2021-47482? +
CVE-2021-47482 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47482? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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