VulnerabilityPublished 20 Mar 2026Updated 23 Mar 2026

CVE-2026-31381: Gainsight Assist · Use of GET request method with sensitive query strings

Affects Gainsight AssistSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium.

Data as of 31 Oct 2026, 08:20 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
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: 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: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 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 30 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

Affected software

Product	Affected	Fixed in
GainsightGainsight Assist	Affected–	Fixed in–

AI-suggested

To mitigate CVE-2026-31381, organizations using Gainsight Assist should immediately review their OAuth implementation and avoid transmitting sensitive information such as email addresses in URL query parameters, especially in GET requests. Instead, sensitive data should be passed securely using POST requests or stored in encrypted session tokens or secure cookies. Implementing OAuth state parameters that do not contain PII or sensitive data is critical. Additionally, organizations should enable strict logging and monitoring of OAuth callback URLs to detect any unauthorized access attempts. Network traffic should be encrypted using TLS to prevent interception of URLs. Gainsight should be engaged to provide official patches or updates addressing this issue. Until a patch is available, organizations may consider deploying web application firewalls (WAFs) to detect and block suspicious requests containing base64-encoded email addresses in URLs. Educating developers and security teams on secure OAuth practices and regular security assessments of third-party integrations are also recommended to prevent similar vulnerabilities.

Description

An attacker can extract user email addresses (PII) exposed in base64 encoding via the state parameter in the OAuth callback URL.

Impact

The primary impact of CVE-2026-31381 is the unauthorized disclosure of user email addresses, which are considered sensitive personal information. Exposure of these email addresses can lead to privacy breaches and increase the risk of targeted phishing campaigns, identity theft, and social engineering attacks against affected users. For organizations, this can result in reputational damage, regulatory penalties under data protection laws such as GDPR or CCPA, and loss of customer trust. Although the vulnerability does not affect system integrity or availability, the confidentiality breach alone can have significant consequences, especially for organizations handling large volumes of customer data. Since exploitation requires only network access and no authentication or user interaction, attackers can easily harvest exposed emails if they can intercept or access the OAuth callback URLs. This risk is heightened in environments where network traffic is monitored or logged. The lack of known exploits in the wild suggests limited current impact, but the vulnerability remains a concern until properly mitigated.

CWE-598Use of HTTP Request With Sensitive Query String (opens in a new tab)
Variant weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The web application uses an HTTP method to process a request, but the request includes sensitive information in the query string.
Implementation
When sending sensitive information, only include it in the request body or request headers instead of the query string. This may require avoiding use of GET requests.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Web Service Security (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V3.1.1 (opens in a new tab)
V13.1.3 (opens in a new tab)
V8.3.4 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Mar 2026, 19:22 UTC

WeaknessesCWE-598

Technical details

References

Community reviews

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