CVE-2025-40043: linux
Vulnerability summary
CVE-2025-40043 is a high (CVSS 8.8) vulnerability in linux. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 50 · Related 46Timeline
- 28-10-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: net: nfc: nci: Add parameter validation for packet data Syzbot reported an uninitialized value bug in nci_init_req, which was introduced by commit 5aca7966d2a7 ("Merge tag 'perf-tools-fixes-for-v6.17-2025-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools"). This bug arises due to very limited and poor input validation that was done at nic_valid_size(). This validation only validates the skb->len (directly reflects size provided at the userspace interface) with the length provided in the buffer itself (interpreted as NCI_HEADER). This leads to the processing of memory content at the address assuming the correct layout per what opcode requires there. This leads to the accesses to buffer of `skb_buff->data` which is not assigned anything yet. Following the same silent drop of packets of invalid sizes at `nic_valid_size()`, add validation of the data in the respective handlers and return error values in case of failure. Release the skb if error values are returned from handlers in `nci_nft_packet` and effectively do a silent drop Possible TODO: because we silently drop the packets, the call to `nci_request` will be waiting for completion of request and will face timeouts. These timeouts can get excessively logged in the dmesg. A proper handling of them may require to export `nci_request_cancel` (or propagate error handling from the nft packets handlers).
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.31%
Chance of exploitation in the next 30 days
Percentile
23%
Versus all other CVEs
30-day change
+0.02 pp
From 0.29% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu153 products
- linuxAll versions (No fix recorded) | < 5.15.0-170.180 | < 6.8.0-106.106 | < 6.17.0-14.14
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1100.107 | < 6.8.0-1050.53 | < 6.17.0-1007.7
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian1 product
- linux< 6.1.158-1 | < 6.12.57-1 | < 6.17.6-1
Linux1 product
- linux≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < 8fcc7315a10a84264e55bb65ede10f0af20a983f | ≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < bfdda0123dde406dbff62e7e9136037e97998a15 | ≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < 0ba68bea1e356f466ad29449938bea12f5f3711f | ≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < 74837bca0748763a77f77db47a0bdbe63b347628 | ≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < c395d1e548cc68e84584ffa2e3ca9796a78bf7b9 | ≥ 6a2968aaf50c7a22fced77a5e24aa636281efca8, < 9c328f54741bd5465ca1dc717c84c04242fac2e1 | 3.2
3 vendors · 155 products
