CVE-2020-28024: exim Out-of-bounds Write
CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2020-28024DEBIAN-CVE-2020-28024
Published 06-05-2021Last modified 04-08-2024
Vulnerability summary
CVE-2020-28024 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in exim. EPSS estimates a 4.15% chance of exploitation in the next 30 days, higher than 90.7% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (NVD)EPSS score
4.15%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 8 · Related 6Timeline
- 06-05-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Exim 4 before 4.94.2 allows Buffer Underwrite that may result in unauthenticated remote attackers executing arbitrary commands, because smtp_ungetc was only intended to push back characters, but can actually push back non-character error codes such as EOF.
CVSS metrics
4 scores · 3 sources · 2 versionsCritical 9.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
High 7.5Preferred score · NVD (NIST)
AV:N/AC:L/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
4.15%
Chance of exploitation in the next 30 days
Percentile
91%
Versus all other CVEs
30-day change
0.00 pp
From 4.15% on 19-09-2026
19-09-202619-10-2026
EPSS score4.15%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- exim4< 4.94.2-1
Exim1 product
- exim≥ 4.00, < 4.94.2
Ubuntu1 product
- exim4< 4.82-3ubuntu2.4+esm3 | < 4.86.2-2ubuntu2.6+esm1 | < 4.90.1-1ubuntu1.8 | < 4.93-13ubuntu1.5
3 vendors · 3 products
References
6 links- www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28024-UNGET.txtX Refsource MISCThird Party Advisory
