CVE-2021-36980

Process crash via stale RAW_ENCAP pointer

Published Jul 20, 2021 · Updated May 5, 2025

Use-after-free in Open vSwitch 2.11.0 through 2.15.0 allows local users to crash a decoding process via a crafted RAW_ENCAP action. In decode_NXAST_RAW_ENCAP, decode_ed_prop() can reallocate the output buffer, but the decoder retains the old encap pointer and writes through freed memory. Triggering the crash requires local processing of the crafted action with user interaction; the published impact is limited to service interruption.

CVSS severity5.5
Medium
EPSS probability1.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Open vSwitch 2.11.0 through 2.15.0 allows local users to crash a decoding process via a crafted RAW_ENCAP action. In decode_NXAST_RAW_ENCAP, decode_ed_prop() can reallocate the output buffer, but the decoder retains the old encap pointer and writes through freed memory. Triggering the crash requires local processing of the crafted action with user interaction; the published impact is limited to service interruption.

The record

CVE
CVE-2021-36980
Published
Jul 20, 2021
Updated
May 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2021CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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