Answer in brief
CVE-2026-98852 records a Unknown severity vulnerability in net: extend IPv6 exthdr detection of tunneled packets. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=33670f780e0120c3dacda188c512bbffe0b6044c <44ba9dc568c878b699d05e7cf699572dc9df4b59 || >=a98b78116a27e2a57b696b569b2cb431c95cf9b6 <aa480f05aed7a9eee87d4a6fc90647fe9679c670 || >=c4336a07eb6b2526dc2b62928b5104b41a7f81f5 <cabacdf98e09eb74599c4d97d7bd7fd659598fb7 || >=c4336a07eb6b2526dc2b62928b5104b41a7f81f5 <5f0764cb1c81a9712bce605d38efe6d844a70b29 || 2094a7cf91b71367b649f991aacc7b579f793d0b || ed71cf465c75f5688b07a35d373cd1d6b589c8ea || 732fdeb2987c94b439d51f5cb9addddc2fc48c42 || >=6.12.81 <6.12.113 || >=6.18.22 <6.18.56 || >=6.1.168 <6.2 || >=6.6.134 <6.7 || >=6.19.12 <6.20 | 44ba9dc568c878b699d05e7cf699572dc9df4b59, aa480f05aed7a9eee87d4a6fc90647fe9679c670, cabacdf98e09eb74599c4d97d7bd7fd659598fb7, 5f0764cb1c81a9712bce605d38efe6d844a70b29, 6.12.113, 6.18.56, 6.2, 6.7, 6.20 |
| Linux/Linuxgeneric | 7.0 | Not reported |
| Linux/Linuxgeneric | >=ed71cf465c75f5688b07a35d373cd1d6b589c8ea <fdbd83c2d929ec968b37d2f75149a79440e328ff || >=33670f780e0120c3dacda188c512bbffe0b6044c <44ba9dc568c878b699d05e7cf699572dc9df4b59 || >=a98b78116a27e2a57b696b569b2cb431c95cf9b6 <aa480f05aed7a9eee87d4a6fc90647fe9679c670 || >=c4336a07eb6b2526dc2b62928b5104b41a7f81f5 <cabacdf98e09eb74599c4d97d7bd7fd659598fb7 || >=c4336a07eb6b2526dc2b62928b5104b41a7f81f5 <5f0764cb1c81a9712bce605d38efe6d844a70b29 || 2094a7cf91b71367b649f991aacc7b579f793d0b || 732fdeb2987c94b439d51f5cb9addddc2fc48c42 || >=6.6.134 <6.6.160 || >=6.12.81 <6.12.113 || >=6.18.22 <6.18.56 || >=6.1.168 <6.2 || >=6.19.12 <6.20 | fdbd83c2d929ec968b37d2f75149a79440e328ff, 44ba9dc568c878b699d05e7cf699572dc9df4b59, aa480f05aed7a9eee87d4a6fc90647fe9679c670, cabacdf98e09eb74599c4d97d7bd7fd659598fb7, 5f0764cb1c81a9712bce605d38efe6d844a70b29, 6.6.160, 6.12.113, 6.18.56, 6.2, 6.20 |
Published upstream
Oct 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 18, 2026
In the Linux kernel, the following vulnerability has been resolved: net: extend IPv6 exthdr detection of tunneled packets Commit c4336a07eb6b ("net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback") split skb_gso_has_extension_hdr() into mutually exclusive branches on skb->encapsulation. This did not yet address all paths: 1. With skb->encapsulation set, the outer header is not checked. IPv6 tunnels such as ip6_gre and ip6_tunnel add an outer Destination Options header by default (encap_limit). Their GSO packets skip software GSO, then skb_csum_hwoffload_help() sees the outer extension header and calls skb_checksum_help() on the GSO skb, which warns and drops it. 2. Tunnels over IPv6 without an outer transport header, such as ip6_tunnel, leave skb->transport_header at the inner transport header. skb_network_header_len() then spans the outer IPv6, tunnel and inner IP headers, a false positive. 3. UDP tunnels without an inner network header, such as SCTP-in-UDP or PSP, have no inner IPv6 header to check. Decide on the outer header alone. 4. Directly dereferencing inner_ip_hdr(skb)->version without skb_header_pointer() is unsafe. Instead, check ipv6_ext_hdr(nexthdr) on the outer IPv6 header and, if set, on the inner IPv6 header. Read the headers with skb_header_pointer(). Keep the skb_network_header_len() check when !skb->encapsulation to also catch encapsulated packets without skb->encapsulation (e.g., virtio). Use the same helper in skb_csum_hwoffload_help(). Its open coded test has the false positive of (2) and ignores the inner header. Background: checksum offload of tunneled packets invariants: Non-GSO skb: - If the inner packet is CHECKSUM_PARTIAL, Local Checksum Offload computes the outer checksum in software and the device offloads only the inner L4 checksum. - If the inner packet is CHECKSUM_NONE (e.g., SCTP-in-UDP, ESP-in-UDP, Remote Checksum Offload), the device offloads the outer UDP or GRE checksum instead. GSO skb: - A device with NETIF_F_GSO_UDP_TUNNEL_CSUM or NETIF_F_GSO_GRE_CSUM computes both inner and outer checksums per segment. The outer checksum is seeded with only the pseudo-header checksum. A NETIF_F_IPV6_CSUM device must parse through the outer headers to reach the inner ones.
Quoted source text, attributed separately from HOL analysis.