VulnerabilityPublished 10 Nov 2026

CVE-2026-125709: Red Hat Enterprise Linux 10 · Out-of-bounds Write

Affects Red Hat Enterprise Linux 10Source CVE Database V5

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Not known to be exploited · CVSS 4.2 Medium.

Data as of 10 Nov 2026, 11:48 UTC

CVSS 3.1 base score

4.2Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	4.2

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

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

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: None: There is no loss of confidentiality within 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 10 Nov 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 10 Nov 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

Affected software

Product	Affected	Fixed in
Red Hat Enterprise Linux 10gcc	Affected–	Fixed in–
Red Hat Enterprise Linux 10gcc-toolset-15-gcc	Affected–	Fixed in–
Red Hat Enterprise Linux 10gcc-toolset-16-gcc	Affected–	Fixed in–
Red Hat Enterprise Linux 10mingw-gcc	Affected–	Fixed in–
Red Hat Enterprise Linux 6compat-gcc-295	Affected–	Fixed in–
Red Hat Enterprise Linux 6compat-gcc-296	Affected–	Fixed in–

AI-suggested

Red Hat has not explicitly stated a patch availability in the provided advisory. The vulnerability requires specific conditions to exploit, and standard system utilities are not vulnerable. Users should review the Red Hat advisory for updates and consider applying any forthcoming patches or mitigations. If using custom or network-exposed services that perform single-character output under failure conditions, consider mitigating the ability to induce repeated filesystem write failures or update the affected libstdc++ library once a fix is released. Monitoring Red Hat's official advisory page is recommended for patch status updates.

Description

CVE-2026-125709 is a vulnerability in the libstdc++ library used by Red Hat Enterprise Linux 10. It involves an out-of-bounds write triggered when a byte-by-byte write operation fails during file stream processing, causing the library to append data beyond the intended buffer. Exploitation requires specific application designs combined with induced repeated filesystem write failures. This can lead to denial of service or memory corruption. Standard system utilities and privileged binaries are not affected, limiting practical exploitation to custom or network-exposed services that use vulnerable single-character output routines under failure conditions.

Impact

The vulnerability can cause denial of service through service termination or localized memory corruption in affected applications. It does not impact confidentiality but may allow integrity modification or availability disruption. Practical exploitation is limited due to the need for specific application designs and induced repeated filesystem write errors. Standard system utilities and privileged binaries shipped with Red Hat Enterprise Linux 10 are not affected, reducing the overall risk in typical deployments.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 11:48 UTC

Technical details

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