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TI-2026-45180 Aliases CVE-2026-63380

Libevent: Null Pointer Dereference in `evws_new_session`

Priority MEDIUM 59CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 6 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0014 3rd percentileScored 2026-11-07
Fix Partial libevent (libevent): 2.2.2-alphaRed Hat: 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
libeventlibeventbefore 2.2.2-alpha2.2.2-alphaPatch availableCNA
  • libevent Vendorlibevent Affected before 2.2.2-alpha Fixed in 2.2.2-alpha Patch available CNA

Remediation

  • Fix · CNA libevent (libevent) Fixed in 2.2.2-alpha

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred
Not affected: 2 products
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-63380
  2. 2026-11-06 Affected versions changed · Red Hat

References

Other 3

  • TI-2026-45182 libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling CVSS 4.0CRITICAL 9.2
  • TI-2026-45184 Libevent: `evtag_unmarshal_header()` decodes a wire `uint32` length into a signed `int` return value. CVSS 4.0HIGH 8.7
  • TI-2026-45183 Libevent: decode_tag_internal() can lead to out-of-bounds read CVSS 4.0HIGH 8.7
  • TI-2026-45237 Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames CVSS 3.1HIGH 7.5
  • TI-2026-45187 Libevent: Off-by-one stack buffer overflow in dnsname_to_labels via crafted DNS server response CVSS 3.1HIGH 7.0
  • TI-2026-45185 Libevent: HTTP header handling bugs create risk of access control bypass. CVSS 4.0CRITICAL 9.2
See all 9 →

Sources

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