Out-of-bounds Read in Linux

CVE-2025-39839

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix OOB read/write in network-coding decode batadv_nc_skb_decode_packet() trusts coded_len and checks only against skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing payload headroom, and the source skb length is not verified, allowing an out-of-bounds read and a small out-of-bounds write. Validate that coded_len fits within the payload area of both destination and source sk_buffs before XORing.

Vulnerability class: Buffer Overflow

EPSS: 0.002 (6.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-39839?
CVE-2025-39839 is a high-severity vulnerability in Linux, classified under Out-of-bounds Read. CVSS score: 8.8/10. Published 2025-09-19.
How severe is CVE-2025-39839?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2025-39839 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.