CVE-2026-49825VulnerabilityPublished 9 Sep 2026Updated 26 Oct 2026

Red Hat Security Advisory: python-lxml security update

Affects Red Hat python-lxmlSource GCVE Database

Authoritative record:CVE-2026-49825· High 8.2

Not known to be exploited · CVSS 8.2 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

8.2High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: High
Integrity: Low
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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: 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 Aug 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 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

AI-suggested

Red Hat has released updated python-lxml packages that address this vulnerability. Users of Red Hat Enterprise Linux 9 and its variants should apply the provided updates as detailed in the Red Hat advisory (RHSA-2026:66204) to remediate the issue. The vendor advisory provides instructions for applying the update. No additional mitigation steps are indicated beyond applying the official patch.

Description

A security vulnerability (CVE-2026-49825) was identified in the python-lxml package used in Red Hat Enterprise Linux 9. The issue is a URL bypass vulnerability in the lxml HTML cleaner component caused by a missing xlink:href attribute. Red Hat has issued an important security update to address this vulnerability in python-lxml. The update is available for multiple architectures and variants of Red Hat Enterprise Linux 9. No public exploit or active exploitation in the wild is currently known.

Impact

The vulnerability allows a URL bypass in the lxml HTML cleaner, which could lead to improper sanitization of HTML content. This may allow malicious URLs or content to evade filtering, potentially leading to security issues in applications relying on this library for HTML sanitization. The Red Hat advisory rates the security impact as important, indicating a high severity level. There is no evidence of exploitation in the wild at this time.

Summary

The vulnerability CVE-2026-49825 affects the python-lxml library's HTML cleaner functionality, where a missing xlink:href attribute allows a URL bypass. This flaw could potentially allow malicious content to bypass the cleaning process. Red Hat has released an updated python-lxml package for Red Hat Enterprise Linux 9 and its variants to fix this issue. The advisory rates the impact as important (high severity) and provides updated packages for various architectures including x86_64, s390x, ppc64le, and aarch64. No CVSS score is provided, and no known exploits in the wild have been reported.

CWE-166Improper Handling of Missing Special Element (opens in a new tab)
Base weakness
The product receives input from an upstream component, but it does not handle or incorrectly handles when an expected special element is missing.
Developers should anticipate that special elements will be removed in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
V5.2.2 (opens in a new tab)
V5.2.7 (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

Description

AI analysisMachine-generated, updated 26 Oct 2026, 17:13 UTC

WeaknessesCWE-166

Technical details

References

Community reviews

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