Exim 4 before 4.94.2 allows an off-by-two Out-of-bounds Write because "-F ''" is mishandled by parse_fix_phrase.
- Published
- May 6, 2021
- Updated
- Jun 16, 2026
- EPSS
- 0.4% · 31th percentile
- CWE
- CWE-787
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| exim | exim | cpe:2.3:a:exim:exim |
Using exim? Add it to your stack and be the first to know about CVEs like this one. (Email server)
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- exim exim4.00 and later · before 4.94.2
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | exim4 | before 4.94.2-1 | 4.94.2-1 |
| openSUSE:Leap 15.2 | exim | before 4.94.2-lp152.8.3.1 | 4.94.2-lp152.8.3.1 |
| openSUSE:Tumbleweed | exim | before 4.94.2-4.2 | 4.94.2-4.2 |
| SUSE:Package Hub 15 SP1 | exim | before 4.94.2-bp151.2.4.1 | 4.94.2-bp151.2.4.1 |
| SUSE:Package Hub 15 SP1 | libspf2 | before 1.2.10-bp151.4.1 | 1.2.10-bp151.4.1 |
| SUSE:Package Hub 15 SP2 | exim | before 4.94.2-bp152.6.4.1 | 4.94.2-bp152.6.4.1 |
| SUSE:Package Hub 15 SP2 | libspf2 | before 1.2.10-bp152.5.1 | 1.2.10-bp152.5.1 |
Same product
exim: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-10149A flaw was found in Exim versions 4.87 to 4.91 (inclusive).KEV99Now
- CVE-2018-6789An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1.KEV94Now
- CVE-2010-4344Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70 allows remote attackers to execute arbitrary code KEV91Now
- CVE-2019-16928Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846.KEV81Now
- CVE-2010-4345Exim 4.72 and earlier allows local users to gain privileges by leveraging the ability of the exim user account to specify an alternate confiKEV66This week
- CVE-2025-26794Exim 4.98 before 4.98.1, when SQLite hints and ETRN serialization are used, allows remote SQL injection.62This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:exim4 | 4.94.2-1 · Debian:12 | Package registry (OSV) |
| opensuse:exim | 4.94.2-lp152.8.3.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| suse:exim | 4.94.2-bp151.2.4.1 · SUSE:Package Hub 15 SP1 | Package registry (OSV) |
| suse:libspf2 | 1.2.10-bp151.4.1 · SUSE:Package Hub 15 SP1 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.