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CVE Record

CVE-2023-53517: tipc: do not update mtu if msg_max is too small in mtu negotiation

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-53517 is a Linux kernel TIPC flaw where a malicious peer can send an invalidly small MTU during negotiation. The kernel may calculate an enormous value, allocate excessive network buffer memory, and crash. Business risk is mainly service disruption on systems that use TIPC.

Executive priority

Treat this as a targeted availability risk, not a confirmed mass-exploitation emergency. Patch exposed or TIPC-dependent Linux systems in normal priority order, faster where downtime would affect critical services.

Technical view

The bug is in TIPC link MTU negotiation. tipc_link_proto_rcv() could accept an MTU below the bearer minimum, causing underflow in tipc_link_mss(). The fix rejects MTU updates below tipc_bearer_min_mtu(). Sources describe warning spam, huge skb allocation, and a general protection fault.

Likely exposure

Exposure appears limited to Linux systems with TIPC enabled and reachable by a peer able to participate in TIPC negotiation. The source bundle does not prove broad internet exposure or affected distribution package versions.

Exploitation context

The CVE record describes a malicious peer sending a very small MTU value and causing kernel instability or crash. KEV is false, and the provided sources do not report active exploitation or public weaponization.

Researcher notes

Affected-version metadata in the bundle is incomplete and should be validated against kernel stable branches or distribution advisories. The primary security impact evidenced by sources is denial of service through kernel crash, not data theft or privilege escalation.

Mitigation direction

  • Apply Linux kernel updates containing the referenced TIPC MTU validation fix.
  • Check distribution vendor advisories for fixed kernel package versions.
  • Prioritize systems where TIPC is enabled or used for clustered services.
  • Restrict TIPC exposure to trusted peers according to vendor guidance.

Validation and detection

  • Inventory Linux kernels and identify hosts with TIPC enabled or loaded.
  • Check package changelogs for CVE-2023-53517 or the referenced stable commits.
  • Review kernel logs for TIPC MTU warnings or related crashes.
  • Confirm updated kernels are running after maintenance windows.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxed193ece2649c194a87a9d8470195760d367c075, ed193ece2649c194a87a9d8470195760d367c075, ed193ece2649c194a87a9d8470195760d367c075, ed193ece2649c194a87a9d8470195760d367c075, ed193ece2649c194a87a9d8470195760d367c075unaffected
LinuxLinux4.1, 0, 5.10.181, 5.15.113, 6.1.30, 6.3.4, 6.4affected
Weakness

CWE details

No CWE listed

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