VulnerabilityPublished 6 Nov 2026

CVE-2026-123664: gcn.nasa.gov · Improper Authorization

Affects gcn.nasa.govSource CVE Database V5

Compare

Public exploit available · CVSS 5.3 Medium.

Data as of 6 Nov 2026, 15:04 UTC

CVSS 4.0 base score

5.3Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (VulDB)	CVSS 4.0	5.3
CNA (VulDB)	CVSS 3.1	5.4
CNA (VulDB)	CVSS 3.0	5.4
CNA (VulDB)	CVSS 2.0	5.5

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system 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 to the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 6 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
nasa-gcngcn.nasa.gov	Affected =b299b562af665878964b981a459f0a9c04b11adf	Fixed in–

CPE configurations (1)

cpe:2.3:a:nasa-gcn:gcn.nasa.gov:*:*:*:*:*:*:*:*

AI-suggested

A fix for this vulnerability exists in a pending pull request but has not yet been accepted or deployed. Until the fix is merged and applied, users should monitor the project's updates closely and apply the patch as soon as it becomes available. No vendor advisory or official patch release is currently available.

Description

CVE-2026-123664 is an improper authorization vulnerability in the Email Notification Handler component of nasa-gcn's gcn.nasa.gov system. The flaw involves manipulation of the Recipient argument in the /user/email processing, allowing unauthorized actions remotely. The issue affects versions up to commit b299b562af665878964b981a459f0a9c04b11adf. A fix has been developed but is pending acceptance in a pull request. Exploit code has been publicly released, increasing the risk of exploitation. The product uses a rolling release model, so specific affected versions are not defined.

Impact

Successful exploitation allows an attacker to perform unauthorized actions related to email notifications by manipulating the Recipient argument remotely. This could lead to unauthorized access or actions within the system's email notification functionality. The CVSS 4.0 base score is 5.3 (medium severity), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and limited impact on confidentiality, integrity, and availability.

Summary

This vulnerability in nasa-gcn's gcn.nasa.gov system arises from improper authorization checks in the Email Notification Handler component, specifically in the handling of the Recipient argument in the /user/email endpoint. An attacker can remotely manipulate this argument to bypass authorization controls. The flaw affects all versions up to the specified commit b299b562af665878964b981a459f0a9c04b11adf. Although a fix has been created, it is not yet merged or deployed. Public exploit code is available, which may facilitate attacks. Due to the rolling release strategy, exact affected versions cannot be enumerated.

References

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