CVE-2017-7806: A use-after-free vulnerability can occur when the layer manager is freed too early when rendering specific SVG content, resulting in a potentially exploitable crash

Distribution release	Source package	Vendor state	Fixed version	Evidence
Debian sidsid · source	`firefox`	Vendor fix publishedDebian records a fixed source-package version for this release.	`55.0-1`	Debian Security Tracker ↗Source updated 5 Oct 2026

Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available

What, why and how

A use-after-free vulnerability can occur when the layer manager is freed too early when rendering specific SVG content, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 55.

What

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

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

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

Reference recorded

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: a network path → Use After Free → disrupt the affected service
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's 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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Common Vulnerability Scoring System 3.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedDenial of serviceCWE-416Public exploit reference

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2017-16781Official EUVD mapping

0 linked advisory records.

Official EUVD record ↗

BSI · German · WID-SEC-2025-1211Mozilla Firefox: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Mozilla Firefox ESR und Mozilla Firefox ausnutzen, um Benutzer zu täuschen, Sicherheitsvorkehrungen zu umgehen, Informationen offenzulegen, beliebigen Programmcode mit den Rechten des Angegriffenen auszuführen und einen Denial of Service Zustand herbeizuführen.

Official advisory ↗

Canadian Centre for Cyber Security · English · AV17-121Mozilla security updates

bring attention to the recently released security update for Mozilla Firefox. Assessment Mozilla released security updates to address multiple vulnerabilities in Firefox. The severity of these issues ranges from low to critical. Version affected: Firefox 55 CVE References: CVE-2017-7753, CVE-2017-7779, CVE-2017-7780 , CVE-2017-7781, CVE-2017-7782, CVE-2017-7783, CVE-2017-7784, CVE-2017-7785, CVE-2017-7786, CVE-2017-7787, CVE-2017-7788,CVE-2017-7789, CVE-2017-7790, CVE-2017-7791, CVE-2017-7792, CVE-2017-7794, CVE-2017-7796, CVE-2017-7797, CVE-2017-7798, CVE-2017-7799, CVE-2017-7800, CVE-2017-7801, CVE-2017-7802, CVE-2017-7803, CVE-2017-7804, CVE-2017-7806, CVE-2017-7807,CVE-2017-7808 Suggested action CCIRC recommends that system administrators test and deploy the vendor-released updates to affected applications accordingly. References https://www.mozilla.org/en-US/security/advisories/mfsa2017-18/

Official advisory ↗

CERT-FR · French · CERTFR-2017-AVI-256Multiples vulnérabilités dans Mozilla Firefox

.cve.org/CVERecord?id=CVE-2017-7796 Référence CVE CVE-2017-7797 https://www.cve.org/CVERecord?id=CVE-2017-7797 Référence CVE CVE-2017-7798 https://www.cve.org/CVERecord?id=CVE-2017-7798 Référence CVE CVE-2017-7799 https://www.cve.org/CVERecord?id=CVE-2017-7799 Référence CVE CVE-2017-7800 https://www.cve.org/CVERecord?id=CVE-2017-7800 Référence CVE CVE-2017-7801 https://www.cve.org/CVERecord?id=CVE-2017-7801 Référence CVE CVE-2017-7802 https://www.cve.org/CVERecord?id=CVE-2017-7802 Référence CVE CVE-2017-7803 https://www.cve.org/CVERecord?id=CVE-2017-7803 Référence CVE CVE-2017-7804 https://www.cve.org/CVERecord?id=CVE-2017-7804 Référence CVE CVE-2017-7806 https://www.cve.org/CVERecord?id=CVE-2017-7806 Référence CVE CVE-2017-7807 https://www.cve.org/CVERecord?id=CVE-2017-7807 Référence CVE CVE-2017-7808 https://www.cve.org/CVERecord?id=CVE-2017-7808 Référence CVE CVE-2017-7809 https://www.cve.org/CVERecord?id=CVE-2017-7809 Gestion détaillée du document le 09 août 2017 version initiale. Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Premier Ministre / Secrétariat Général de la Défense et de la Sécurité Nationale / Agence nationale de la sécurité des systèmes

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2017-013802Firefox における解放済みメモリの使用に関する脆弱性

Firefox には、解放済みメモリの使用に関する脆弱性が存在します。

Official advisory ↗

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: Firefox: unspecified < 55
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 11 Jun 2018 · Last source change 5 Aug 2024, 16:12 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-01

European sourceENISA EUVD · EUVD-2017-16781

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceNIST NVD

NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

1 Sep 2026, 02:42 UTC
ENISA EUVD mappingEUVD-2017-16781 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2017-16781"}
ENISA EUVD ↗
5 Aug 2024, 16:12 UTC
Vendor guidanceAuthoritative vendor guidance changed: added patch: bugzilla.mozilla.org/show_bug.cgi?id=1378113; added remediation: bugzilla.mozilla.org/show_bug.cgi?id=1378113; 1 further additions.
Before
no authoritative guidance recorded
After
patch: bugzilla.mozilla.org/show_bug.cgi?id=1378113 · remediation: bugzilla.mozilla.org/show_bug.cgi?id=1378113 · vendor advisory: mozilla.org/mfsa2017-18
bugzilla.mozilla.org ↗
5 Aug 2024, 16:12 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
unspecified < 55 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
unspecified < 55 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
CNA ↗
5 Aug 2024, 16:12 UTC
Remediation statusRemediation status changed from Awaiting fix to Patch available.
Before
Awaiting fix
After
Patch available
bugzilla.mozilla.org ↗
5 Aug 2024, 16:12 UTC
Public exploit evidencePublic exploit evidence changed from No public exploit to Public exploit reference.
Before
No public exploit
After
Public exploit reference
bugzilla.mozilla.org ↗
5 Aug 2024, 16:12 UTC
SeveritySeverity changed from Unknown to High.
Before
Unknown
After
High
NIST NVD ↗
5 Aug 2024, 16:12 UTC
CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Before
not recorded
After
7.5 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
NIST NVD ↗
5 Aug 2024, 16:12 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2018-06-11CVE published

2024-08-05Fixed release or patch reference recorded

ENISA EUVD · EUVD-2017-16781↗Vendor advisory↗Public exploit reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

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.

A use-after-free vulnerability can occur when the layer manager is freed too early when rendering specific SVG content, resulting in a potentially exploitable crash

Published severity in operational context

Evidence used

Compensating controls

Verification

Release-specific package status

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2017-16781

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication