CVE-2023-53517: tipc: do not update mtu if msg_max is too small in mtu negotiation
Vulnerability summary
CVE-2023-53517 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 23.3% of scored vulnerabilities.
Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 1Timeline
- 01-10-2025PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: tipc: do not update mtu if msg_max is too small in mtu negotiation When doing link mtu negotiation, a malicious peer may send Activate msg with a very small mtu, e.g. 4 in Shuang's testing, without checking for the minimum mtu, l->mtu will be set to 4 in tipc_link_proto_rcv(), then n->links[bearer_id].mtu is set to 4294967228, which is a overflow of '4 - INT_H_SIZE - EMSG_OVERHEAD' in tipc_link_mss(). With tipc_link.mtu = 4, tipc_link_xmit() kept printing the warning: tipc: Too large msg, purging xmit list 1 5 0 40 4! tipc: Too large msg, purging xmit list 1 15 0 60 4! And with tipc_link_entry.mtu 4294967228, a huge skb was allocated in named_distribute(), and when purging it in tipc_link_xmit(), a crash was even caused: general protection fault, probably for non-canonical address 0x2100001011000dd: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 6.3.0.neta #19 RIP: 0010:kfree_skb_list_reason+0x7e/0x1f0 Call Trace: <IRQ> skb_release_data+0xf9/0x1d0 kfree_skb_reason+0x40/0x100 tipc_link_xmit+0x57a/0x740 [tipc] tipc_node_xmit+0x16c/0x5c0 [tipc] tipc_named_node_up+0x27f/0x2c0 [tipc] tipc_node_write_unlock+0x149/0x170 [tipc] tipc_rcv+0x608/0x740 [tipc] tipc_udp_recv+0xdc/0x1f0 [tipc] udp_queue_rcv_one_skb+0x33e/0x620 udp_unicast_rcv_skb.isra.72+0x75/0x90 __udp4_lib_rcv+0x56d/0xc20 ip_protocol_deliver_rcu+0x100/0x2d0 This patch fixes it by checking the new mtu against tipc_bearer_min_mtu(), and not updating mtu if it is too small.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
EPSS trend
Probability
0.30%
Chance of exploitation in the next 30 days
Percentile
23%
Versus all other CVEs
30-day change
Increase +0.01 pp
From 0.30% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu123 products
- linuxAll versions (No fix recorded) | < 5.15.0-83.92
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1044.49
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ ed193ece2649c194a87a9d8470195760d367c075, < 2bd4ff4ffb92113f8acd04dbaed83269172c24b4 | ≥ ed193ece2649c194a87a9d8470195760d367c075, < 575e84d90a74c0b091b3417ba763ebb237aa0a8c | ≥ ed193ece2649c194a87a9d8470195760d367c075, < 259683001d7e879fea4b42084fb6560dd9408a7e | ≥ ed193ece2649c194a87a9d8470195760d367c075, < 1dd7ae5e0cf5a56e513f7ab7ab9570b7496281d2 | ≥ ed193ece2649c194a87a9d8470195760d367c075, < 56077b56cd3fb78e1c8619e29581ba25a5c55e86 | 4.1
- linux_kernel≥ 4.1, < 5.10.181 | ≥ 5.11, < 5.15.113 | ≥ 5.16, < 6.1.30 | ≥ 6.2, < 6.3.4 | 6.4:rc1 | 6.4:rc2
Debian1 product
- linux< 6.1.37-1 | < 6.3.7-1
3 vendors · 126 products
