CVE-2021-47297: net: fix uninit-value in caif_seqpkt_sendmsg
Vulnerability summary
CVE-2021-47297 is a medium (CVSS 5.5) Use of Uninitialized Resource vulnerability in linux. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.3% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 3Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: net: fix uninit-value in caif_seqpkt_sendmsg When nr_segs equal to zero in iovec_from_user, the object msg->msg_iter.iov is uninit stack memory in caif_seqpkt_sendmsg which is defined in ___sys_sendmsg. So we cann't just judge msg->msg_iter.iov->base directlly. We can use nr_segs to judge msg in caif_seqpkt_sendmsg whether has data buffers. ===================================================== BUG: KMSAN: uninit-value in caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343 ___sys_sendmsg net/socket.c:2397 [inline] __sys_sendmmsg+0x808/0xc90 net/socket.c:2480 __compat_sys_sendmmsg net/compat.c:656 [inline]
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.23%
Chance of exploitation in the next 30 days
Percentile
13%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.23% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu87 products
- linuxAll versions (No fix recorded) | < 4.15.0-159.167 | < 5.4.0-88.99
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1112.119 | < 5.4.0-1057.60
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < d9d646acad2c3590e189bb5d5c86ab8bd8a2dfc3 | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < 5c6d8e2f7187b8e45a18c27acb7a3885f03ee3db | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < ffe31dd70b70a40cd6b21b78c1713a23e021843a | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < 452c3ed7bf63721b07bc2238ed1261bb26027e85 | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < 9413c0abb57f70a953b1116318d6aa478013c35d | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < 1582a02fecffcee306663035a295e28e1c4aaaff | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < d4c7797ab1517515f0d08b3bc1c6b48883889c54 | ≥ bece7b2398d073d11b2e352405a3ecd3a1e39c60, < 991e634360f2622a683b48dfe44fe6d9cb765a09 | 2.6.35
- linux_kernel≥ 2.6.35, < 4.4.277 | ≥ 4.5, < 4.9.277 | ≥ 4.10, < 4.14.241 | ≥ 4.15, < 4.19.199 | ≥ 4.20, < 5.4.136 | ≥ 5.5, < 5.10.54 | ≥ 5.11, < 5.13.6 | 5.14:rc1 | 5.14:rc2
Debian1 product
- linux< 5.14.6-1
3 vendors · 90 products
