Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-53208— Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Bluetooth L2CAP层未强制执行信令MTU（MTUsig），接受超过信令MTU的BR/EDR信令数据包，可能导致蓝牙范围内的BR/EDR对等端在配对前发送包含多个L2CAP_ECHO_REQ命令的大型数据包，强制目标设备发送大量ECHO_RSP帧。

AI Predicted 5.3 Difficulty: Easy EPSS 0.12% · P2

Possible ATT&CK Techniques 1 AI

T1498 · Network Denial of Service

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< e05c4ac575b457978a7ef441053394169084869c affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< fa5823126239b3e453fac1a2fe50726c7f4a55e1 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< b20e8a98dd29b121f58fcdf51e8576119aba536a affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 214a2042b16b3c8d798a8b9ef9f36094f13a9859 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< dedc92b96dc1d8919a3bdf2495ede68922ef7ebc affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< e2b8acf9405bd9b1baf1c54dc897b0905db689bf affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< dd214733544427587a95f66dbf3adff072568990 affected
… +10 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-53208

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig net/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR signaling packets up to the channel MTU and dispatches each command without enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer within radio range can send a fixed-channel CID 0x0001 packet that is larger than MTUsig and contains many L2CAP_ECHO_REQ commands before pairing. In a real-radio stock-kernel run, one 681-byte signaling packet containing 168 zero-length ECHO_REQ commands made the target transmit 168 ECHO_RSP frames over about 220 ms. Impact: a Bluetooth BR/EDR peer within radio range, before pairing, can force 168 ECHO_RSP frames from one 681-byte fixed-channel signaling packet containing packed ECHO_REQ commands. Define Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and reject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP carrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched. The Bluetooth Core spec wording for MTUExceeded says the reject identifier shall match the first request command in the packet, and that packets containing only responses shall be silently discarded. Linux intentionally deviates from that prescription: silently discarding desynchronizes the peer because the remote stack never learns its responses were dropped, and locating the first request command requires walking command headers past MTUsig, i.e. processing bytes from a packet we have already decided is too large to process. We therefore always emit one reject and use the identifier from the first command header, a single fixed-offset byte read. The unrestricted BR/EDR signaling parser and ECHO_REQ response path both trace to the initial git import; no later introducing commit is available for a Fixes tag.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Bluetooth L2CAP层未强制执行信令MTU（MTUsig），接受超过信令MTU的BR/EDR信令数据包，可能导致蓝牙范围内的BR/EDR对等端在配对前发送包含多个L2CAP_ECHO_REQ命令的大型数据包，强制目标设备发送大量ECHO_RSP帧。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ~ e05c4ac575b457978a7ef441053394169084869c -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2026-53208

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-53208

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-53208 (8)

Same Patch Batch · Linux · 2026-06-25 · 146 CVEs total

CVE-2026-53176 9.8 CRITICAL IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
CVE-2026-53228 9.8 CRITICAL ipv6: sit: reload inner IPv6 header after GSO offloads
CVE-2026-53151 9.8 CRITICAL rxrpc: Fix the ACK parser to extract the SACK table for parsing
CVE-2026-53221 9.8 CRITICAL ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
CVE-2026-53247 9.8 CRITICAL net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
CVE-2026-53216 9.8 CRITICAL net: mvpp2: limit XDP frame size to the RX buffer
CVE-2026-53260 9.8 CRITICAL tcp: Add preempt_{disable,enable}_nested() in reqsk_queue_hash_req().
CVE-2026-53246 9.8 CRITICAL sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing
CVE-2026-53175 9.8 CRITICAL inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush
CVE-2026-53215 9.8 CRITICAL net: mvpp2: refill RX buffers before XDP or skb use
CVE-2026-53131 9.4 CRITICAL netfilter: require Ethernet MAC header before using eth_hdr()
CVE-2026-53225 9.1 CRITICAL sctp: fix uninit-value in __sctp_rcv_asconf_lookup()
CVE-2026-53224 9.1 CRITICAL sctp: validate embedded INIT chunk and address list lengths in cookie
CVE-2026-53186 9.1 CRITICAL RDMA/srp: bound SRP_RSP sense copy by the received length
CVE-2026-53240 8.8 HIGH xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
CVE-2026-53171 8.8 HIGH accel/ethosu: fix arithmetic issues in dma_length()
CVE-2026-53232 8.8 HIGH net: phy: clean the sfp upstream if phy probing fails
CVE-2026-53159 8.8 HIGH misc: fastrpc: fix DMA address corruption due to find_vma misuse
CVE-2026-53170 8.8 HIGH accel/ethosu: reject DMA commands with uninitialized length
CVE-2026-53188 8.8 HIGH RDMA/core: Validate the passed in fops for ib_get_ucaps()

Showing top 20 of 146 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-53208

No comments yet

Leave a comment