Information Exposure Affecting kernel6.18-debuginfo-common-aarch64 package, versions <1:6.18.56-125.164.amzn2023
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-AMZN2023-KERNEL618DEBUGINFOCOMMONAARCH64-21702858
- published25 Oct 2026
- disclosed9 Oct 2026
Introduced: 9 Oct 2026
NewCVE-2026-98377 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 kernel6.18-debuginfo-common-aarch64 to version 1:6.18.56-125.164.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3251.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel6.18-debuginfo-common-aarch64 package and not the kernel6.18-debuginfo-common-aarch64 package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
vlan: require the MAC header to be present in __vlan_insert_inner_tag()
__vlan_insert_inner_tag() only guarantees head room via skb_cow_head(), never that mac_len bytes of MAC header are present. Its ETH_HLEN wrappers - __vlan_insert_tag() under skb_vlan_push(), and vlan_insert_tag() under validate_xmit_vlan() on the generic transmit path - therefore rewrite the first 16 bytes at skb->data: a 12-byte memmove plus two 2-byte stores at +12 and +14. No caller supplies the bound, while the pop helpers use skb_ensure_writable()/pskb_may_pull().
An IFF_TUN device has hard_header_len == 0, so packet_snd() accepts a one-byte AF_PACKET/SOCK_RAW frame. The first vlan push only sets a hwaccel tag; the next - clsact "action vlan push" or bpf_skb_vlan_push() - enters the helper with skb->len still 1. The head comes from skbuff_small_head without __GFP_ZERO, so each push drags bytes from beyond skb->tail into the frame. After three the one-byte send leaves as 13 bytes carrying 11 bytes of uninitialised slab:
0000: 5a b3 62 12 80 88 ff ff 00 b3 62 12 81 `------------------------------' only 0x5a was sent; the rest is slab, here the top 56 bits of a linear-map address
Require the MAC header the helper rewrites to be present, so such a frame is dropped rather than transmitted.
References
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-98377
- https://git.kernel.org/stable/c/40a5cc4b7251c74f3341332a226d02200e96bccf
- https://git.kernel.org/stable/c/59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc
- https://git.kernel.org/stable/c/ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a
- https://git.kernel.org/stable/c/f42562dd027dc4ed103fae17b2206e73ea1963c4
- https://git.kernel.org/stable/c/3d531429524df2c7116579306640283fea68bcf0