CVE-2026-58203VulnerabilityPublished 13 Aug 2026Updated 29 Oct 2026

mcpm · pydantic-settings: NestedSecretsSettingsSource follows symlinks outside secrets_dir, enabling local file read and

Affects mcpmSource GCVE Database

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Authoritative record:CVE-2026-58203· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 2.15.0_2 when convenient.

Data as of 30 Oct 2026, 07:00 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.15.0_2

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade mcpm to 2.15.0_2.

Affected software

Product	Affected	Fixed in
Homebrewmcpm`pkg:brew/mcpm`Other threats	Affected >=2.9.0_2 <2.15.0_2	Fixed in 2.15.0_2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to pydantic-settings version 2.15.0_2 or later, which fixes the issue by only descending into directories whose resolved paths remain within secrets_dir, using a single cycle-safe iterator for size checking and loading, and skipping files outside secrets_dir. If upgrading is not immediately possible, ensure the secrets_dir is fully controlled and not writable by untrusted users or components, or disable secrets_nested_subdir=True to avoid following symlinks.

Description

The pydantic-settings library's NestedSecretsSettingsSource component improperly follows symbolic links inside a configured secrets directory that point outside this directory. This allows reading files outside the intended secrets directory into application settings, bypassing the configured maximum size limit for secrets loading. The vulnerability requires the ability to place symlinks inside the secrets directory and is not remotely exploitable by itself. It affects versions from 2.9.0_2 up to but not including 2.15.0_2. The issue is fixed in version 2.15.0_2.

Impact

Confidentiality is impacted because files outside the configured secrets_dir can be read into application settings, potentially exposing sensitive local files. The integrity and availability of the secrets_dir_max_size safeguard are compromised because the size limit can be bypassed, and cyclic symlinks can cause excessive resource consumption during secret loading. Exploitation requires the ability to place symlinks inside the secrets directory, so it is not remotely exploitable on its own.

Summary

NestedSecretsSettingsSource in pydantic-settings reads secret values from files under a configured secrets_dir. When secrets_nested_subdir=True, the loader follows symlinked directories inside secrets_dir even if they point outside, while the size check does not account for these symlinked files. This discrepancy allows an attacker or lower-privileged component able to place symlinks inside secrets_dir to cause out-of-tree local file reads and bypass the secrets_dir_max_size limit. The vulnerability also allows cyclic symlinks to inflate resource usage. The flaw affects versions >=2.9.0_2 <2.15.0_2 and is fixed in 2.15.0_2 by enforcing strict path resolution and cycle-safe iteration that excludes files outside secrets_dir.

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Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 07:00 UTC

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