Exim up to 4.99.2 TCP Connection close_notify use after free

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in Exim up to 4.99.2. The affected element is the function close_notify of the component TCP Connection Handler. Such manipulation leads to use after free. This vulnerability is referenced as CVE-2026-45185. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Exim up to 4.99.2 and classified as critical. Affected by this issue is the function close_notify of the component TCP Connection Handler. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.

This vulnerability is handled as CVE-2026-45185 since 05/10/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 4.99.3 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.8
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Exim 4.99.3

Timelineinfo

05/10/2026 CVE reserved
05/12/2026 +2 days Advisory disclosed
05/12/2026 +0 days VulDB entry created
05/12/2026 +0 days VulDB entry last update

Sourcesinfo

Status: Confirmed

CVE: CVE-2026-45185 (🔒)
GCVE (CVE): GCVE-0-2026-45185
GCVE (VulDB): GCVE-100-363380

Entryinfo

Created: 05/12/2026 23:15
Changes: 05/12/2026 23:15 (64)
Complete: 🔍
Cache ID: 216::103

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