VulnerabilityPublished 28 Jan 2026Updated 25 Mar 2026

CVE-2026-1539: Red Hat Enterprise Linux 10 · Insertion of Sensitive Information Into Sent Data

Affects Red Hat Enterprise Linux 10Source CVE Database V5

Not known to be exploited · CVSS 5.8 Medium.

Data as of 26 Oct 2026, 09:16 UTC

CVSS 3.1 base score

5.8Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 19% 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:C/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 28 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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 10libsoup3	Affected–	Fixed in–
Red Hat Enterprise Linux 6libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 7libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 8libsoup	Affected–	Fixed in–
Red Hat Enterprise Linux 9libsoup	Affected–	Fixed in–

AI-suggested

To mitigate CVE-2026-1539, organizations should apply patches or updates provided by Red Hat for libsoup and Red Hat Enterprise Linux 10 as soon as they become available. In the absence of patches, administrators should audit and restrict HTTP redirect behavior in applications using libsoup, particularly those involving proxy authentication. Configuring proxies to limit credential scope and privileges can reduce potential damage if credentials are leaked. Network monitoring should be enhanced to detect unusual outbound HTTP requests carrying proxy credentials. Additionally, developers should review and update application code to ensure that all authentication headers, including Proxy-Authorization, are properly cleared during HTTP redirects. Employing network segmentation and strict access controls around proxy servers can further limit the impact of credential leakage. Finally, consider using alternative HTTP libraries or proxy authentication mechanisms that do not expose credentials during redirects until a fix is applied.

Description

A flaw was found in the libsoup HTTP library that can cause proxy authentication credentials to be sent to unintended destinations. When handling HTTP redirects, libsoup removes the Authorization header but does not remove the Proxy-Authorization header if the request is redirected to a different host. As a result, sensitive proxy credentials may be leaked to third-party servers. Applications using libsoup for HTTP communication may unintentionally expose proxy authentication data.

Impact

The primary impact of CVE-2026-1539 is the potential leakage of proxy authentication credentials to unintended external servers. This can compromise the confidentiality of sensitive proxy credentials, which may allow attackers to impersonate legitimate users or services to access internal networks or resources. Organizations using Red Hat Enterprise Linux 10 with libsoup-based applications that perform HTTP requests through proxies are at risk. The exposure of proxy credentials could facilitate lateral movement within corporate networks, data exfiltration, or further exploitation of internal systems. Although the vulnerability does not affect system integrity or availability directly, the confidentiality breach can lead to significant security incidents, especially in environments relying heavily on proxy authentication for network segmentation and access control. The risk is heightened in environments where redirects to external hosts are common or where proxy credentials have broad access privileges. Since exploitation requires no authentication or user interaction, attackers can remotely trigger the vulnerability, increasing its threat potential.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Mar 2026, 18:50 UTC

Technical details

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