Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 0.35% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-24855High confidence
numbers.c in libxslt before 1.1.43 has a use-after-free because, in nested XPath evaluations, an XPath context node can be modified but never restored
xmlsoft · libxslt
7.8HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict local access and enforce least privilege on affected hosts.
- Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
- Confirm that the asset runs xmlsoft libxslt and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
13 package statesRelease-specific package status
Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Alpine v3.23v3.23 · community | qt5-qtwebengine | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 5.15.17-r10 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.23v3.23 · community | qt6-qtwebengine | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 6.8.2-r3 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.23v3.23 · main | libxslt | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 1.1.43-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.22v3.22 · community | qt5-qtwebengine | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 5.15.17-r10 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.22v3.22 · community | qt6-qtwebengine | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 6.8.2-r3 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.22v3.22 · main | libxslt | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 1.1.43-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.21v3.21 · community | qt5-qtwebengine | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 5.15.17-r7 | Alpine Security Database ↗Source updated 19 Aug 2026 |
| Alpine v3.21v3.21 · main | libxslt | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 1.1.42-r2 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Debian trixietrixie · source | libxslt | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.1.35-1.2 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | libxslt | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.1.35-1+deb12u1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | libxslt | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.1.35-1.2 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | libxslt | Vendor fix publishedDebian records a fixed source-package version for this release. | 1.1.35-1.2 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | libxslt | Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree. | 1.1.39-0exp1ubuntu0.24.04.2 | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2025-24855 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitylibxslt: Use-After-Free in libxslt numbers.c
The vendor explicitly identifies these products as affected by this CVE.
- libxslt as a component of Red Hat Enterprise Linux 6
- libxslt-devel as a component of Red Hat Enterprise Linux 6
- libxslt-python as a component of Red Hat Enterprise Linux 6
- libxslt.src as a component of Red Hat Enterprise Linux 6
- Summary
- A flaw was found in libxslt numbers.c. This vulnerability allows a use-after-free, potentially leading to memory corruption or code execution via nested XPath evaluations where an XPath context node can be modified but not restored.
- Remediation
- For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
numbers.c in libxslt before 1.1.43 has a use-after-free because, in nested XPath evaluations, an XPath context node can be modified but never restored. This is related to xsltNumberFormatGetValue, xsltEvalXPathPredicate, xsltEvalXPathStringNs, and xsltComputeSortResultInternal.
What
numbers.c in libxslt before 1.1.43 has a use-after-free because, in nested XPath evaluations, an XPath context node can be modified but never restored. This is related to xsltNumberFormatGetValue, xsltEvalXPathPredicate, xsltEvalXPathStringNs, and xsltComputeSortResultInternal.
Why
The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.
How
An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
numbers.c in libxslt before 1.1.43 has a use-after-free because, in nested XPath evaluations, an XPath context node can be modified but never restored. This is related to xsltNumberFormatGetValue, xsltEvalXPathPredicate, xsltEvalXPathStringNs, and xsltComputeSortResultInternal.
Why
The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.
How
An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
- Likely attack path
- local access → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Local
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- High: exploitation depends on specific conditions
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-416 ↗
CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Affected
- Fixed
- libxslt-0:1.1.28-9.el7_9.i686 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.ppc as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.s390 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.s390x as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.src as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-0:1.1.28-9.el7_9.x86_64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.i686 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.ppc as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.s390 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.s390x as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.x86_64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.i686 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.ppc as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.ppc64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.ppc64le as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.s390 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.s390x as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-devel-0:1.1.28-9.el7_9.x86_64 as a component of Red Hat Enterprise Linux Server (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.ppc64 as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.ppc64le as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.s390x as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-debuginfo-0:1.1.28-9.el7_9.x86_64 as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-python-0:1.1.28-9.el7_9.ppc64 as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-python-0:1.1.28-9.el7_9.ppc64le as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-python-0:1.1.28-9.el7_9.s390x as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- libxslt-python-0:1.1.28-9.el7_9.x86_64 as a component of Red Hat Enterprise Linux Server Optional (v. 7 ELS)
- and 950 more
- Action
- For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 14 Mar 2025 · Last source change 26 Feb 2026, 19:09 UTC · CWE-416 · Use After Free
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2025-7659
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Red Hat Product Security ↗
- Before
- < 1.1.43 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- < 1.1.43 · Fixed: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
- Remediation statusRemediation status changed from Awaiting fix to Patch available.Red Hat Product Security ↗
- Before
- Awaiting fix
- After
- Patch available
CVE published
Fixed release recorded from official guidance
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.