CVE-2020-28012Known exploitation

Local root escalation via inherited filter pipe

Published May 6, 2021 · Updated Aug 4, 2024

Local privilege escalation in Exim before 4.94.2 allows local users to gain root privileges through an inherited filter pipe. The filter process inherits a writable pipe lacking close-on-exec, allowing crafted length and string data to reach privileged rda_interpret reads and corrupt heap state used for root-owned logging. Exploitation requires local access and allow_filter to be enabled; a demonstrated chain appends controlled data to a chosen root-owned file to create a root account.

CVSS severity7.8
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local privilege escalation in Exim before 4.94.2 allows local users to gain root privileges through an inherited filter pipe. The filter process inherits a writable pipe lacking close-on-exec, allowing crafted length and string data to reach privileged rda_interpret reads and corrupt heap state used for root-owned logging. Exploitation requires local access and allow_filter to be enabled; a demonstrated chain appends controlled data to a chosen root-owned file to create a root account.

The record

CVE
CVE-2020-28012
Published
May 6, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Privilegesauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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