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CVE-2026-64450

Critical Vulnerability: CVE-2026-64450

In the Linux kernel, the following vulnerability has been resolved: tipc: fix out-of-bounds read in broadcast Gap ACK blocks A broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its data area. tipc_get_gap_ack_blks() only verifies that the record's len field is self-consistent with its ugack_cnt/bgack_cnt counts (sz == struct_size(p, gacks, ugack_cnt + bgack_cnt)); it does not check that the record actually fits in the message data area, msg_data_sz(). The unicast caller tipc_l

Monday, July 27, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-64450 is rated CRITICAL โ€” exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.

Executive Summary

In the Linux kernel, the following vulnerability has been resolved:

tipc: fix out-of-bounds read in broadcast Gap ACK blocks

A broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its

data area. tipc_get_gap_ack_blks() only verifies that the record's len

field is self-consistent with its ugack_cnt/bgack_cnt counts

(sz == struct_size(p, gacks, ugack_cnt + bgack_cnt)); it does not check

that the record actually fits in the message data area, msg_data_sz().

The unicast caller tipc_link_proto_rcv() bounds it ("if (glen > dlen)

break;"), but the broadcast caller tipc_bcast_sync_rcv() discards the

returned size, so tipc_link_advance_transmq() copies the record off the

receive skb with an attacker-controlled count:

this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),

GFP_ATOMIC);

A TIPC neighbour that negotiated TIPC_GAP_ACK_BLOCK triggers it with one

ordinary broadcast STATE_MSG (msg_bc_ack_invalid() clear), sized so its

data area is short, carrying a Gap ACK

Why It Matters

CVE-2026-64450 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.1/10

๐Ÿ›ก๏ธWhat Defenders Should Check

  • Check if you are affected โ€” Review your asset inventory for products listed in CVE-2026-64450.
  • Apply available patches โ€” Visit vendor advisories for the latest security updates.
  • Monitor for exploitation โ€” Check your SIEM/IDS logs for related indicators.
  • Use Vulnios to continuously monitor your exposure to CVE-2026-64450 and similar vulnerabilities.

    References & Sources

    How Vulnios Detects This

    Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.

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    Sources

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    Frequently Asked Questions

    What is CVE-2026-64450?

    CVE-2026-64450 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    tipc: fix out-of-bounds read in broadcast Gap ACK blocks

    A broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its

    d

    Am I affected?

    Affected technology is listed in the Affected Products section above. If your asset inventory contains any of them, assume in-scope until you can prove otherwise.

    How urgent is the response?

    Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

    How do I remediate?

    Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

    Where can I track exploitation activity?

    Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2026-64450. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

    How does Vulnios help with this?

    Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.

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