CVE-2021-47482: net: batman-adv: fix error handling
Vulnerability summary
CVE-2021-47482 is a medium (CVSS 5.3) vulnerability in linux. EPSS estimates a 0.74% chance of exploitation in the next 30 days, higher than 54.6% of scored vulnerabilities.
Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 8 · Related 8Timeline
- 22-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.74%
Chance of exploitation in the next 30 days
Percentile
55%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.74% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu87 products
- linuxAll versions (No fix recorded) | < 4.15.0-167.175 | < 5.4.0-92.103
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1119.127 | < 5.4.0-1061.64
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < 0c6b199f09be489c48622537a550787fc80aea73 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < 07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < e50f957652190b5a88a8ebce7e5ab14ebd0d3f00 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < fbf150b16a3635634b7dfb7f229d8fcd643c6c51 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < 6422e8471890273994fe8cc6d452b0dcd2c9483e | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < b0a2cd38553c77928ef1646ed1518486b1e70ae8 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < a8f7359259dd5923adc6129284fdad12fc5db347 | ≥ c6c8fea29769d998d94fcec9b9f14d4b52b349d3, < 6f68cd634856f8ca93bafd623ba5357e0f648c68 | 2.6.38
- linux_kernel≥ 2.6.38, < 4.4.293 | ≥ 4.5, < 4.9.289 | ≥ 4.10, < 4.14.254 | ≥ 4.15, < 4.19.215 | ≥ 4.20, < 5.4.157 | ≥ 5.5, < 5.10.77 | ≥ 5.11, < 5.14.16 | 5.15:rc1 | 5.15:rc2 | 5.15:rc3 | 5.15:rc4 | 5.15:rc5 | 5.15:rc6 | 5.15:rc7
Debian1 product
- linux< 5.15.3-1
3 vendors · 90 products
