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NVD / CVE Program· CNA GitHub_M

CVE-2026-48761: Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes on <object>, <applet>, <iframe>, <img> and the URL Inside <meta http-equiv="refresh"> content

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: symfony (Debian:13) 6.4.41+dfsg-0+deb13u1; symfony (Debian:14) 7.4.13+dfsg-1; symfony/html-sanitizer (Packagist) 6.4.41, 7.4.13, 8.0.13.

Low priority for now. Upgrade to symfony (Debian:13) 6.4.41+dfsg-0+deb13u1; symfony (Debian:14) 7.4.13+dfsg-1; symfony/html-sanitizer (Packagist) 6.4.41, 7.4.13, 8.0.13 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0 until 6.4.41, 7.4.13, and 8.0.13, UrlAttributeSanitizer::getSupportedAttributes() omitted URL-bearing attributes on <object>, <applet>, <iframe>, and <img>, and <meta http-equiv="refresh"> URLs inside content bypassed URL sanitization, allowing explicitly enabled elements or attributes to pass javascript: and similar payloads into sanitized output. This issue is fixed in versions 6.4.41, 7.4.13, and 8.0.13.

MediumCVSS 5.3 · v4.0—No exploit Fix available
Published
Jul 14, 2026
Updated
Jul 21, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
sensiolabssymfony

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • sensiolabs symfony6.1.0 and later · before 6.4.41
  • sensiolabs symfony7.0.0 and later · before 7.4.13
  • sensiolabs symfony8.0.0 and later · before 8.0.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • symfony html-sanitizer

    • >= 6.1.0, < 6.4.41, >= 7.0.0-BETA1, < 7.4.13, >= 8.0.0-BETA1, < 8.0.13affected

  • symfony symfony

    • >= 6.1.0, < 6.4.41, >= 7.0.0-BETA1, < 7.4.13, >= 8.0.0-BETA1, < 8.0.13affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13symfonybefore 6.4.41+dfsg-0+deb13u16.4.41+dfsg-0+deb13u1
Debian:14symfonybefore 7.4.13+dfsg-17.4.13+dfsg-1
Packagistsymfony/html-sanitizerfrom 6.1.0 · before 6.4.416.4.41
Packagistsymfony/html-sanitizerfrom 7.0.0 · before 7.4.137.4.13
Packagistsymfony/html-sanitizerfrom 8.0.0 · before 8.0.138.0.13
Packagistsymfony/symfonyfrom 6.1.0 · before 6.4.416.4.41
Packagistsymfony/symfonyfrom 7.0.0 · before 7.4.137.4.13
Packagistsymfony/symfonyfrom 8.0.0 · before 8.0.138.0.13

Same product

sensiolabs: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-18889An issue was discovered in Symfony 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7.
    49Plan
  • CVE-2018-14773An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through 2.8.43, 3.3.0 through 3.3.17, 3.4.0 through 3.4.13
    43Plan
  • CVE-2019-10910In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, when service ids allow user inp
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-48747Jul 14, 2026 · Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade
    25Monitor
  • ← EarlierCVE-2026-48760Jul 14, 2026 · Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense
    21Monitor
  • Later →CVE-2026-48784Jul 14, 2026 · Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization
    20Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:symfony6.4.41+dfsg-0+deb13u1 · Debian:13Package registry (OSV)
Packagist:symfony/html-sanitizer6.4.41Package registry (OSV)
Packagist:symfony/html-sanitizer7.4.13Package registry (OSV)
Packagist:symfony/html-sanitizer8.0.13Package registry (OSV)
Packagist:symfony/symfony6.4.41Package registry (OSV)
Packagist:symfony/symfony7.4.13Package registry (OSV)
Packagist:symfony/symfony8.0.13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-450720 days apartSymfony: Stored XSS in WebProfiler CodeExtension::fileExcerpt() — Unescaped Non-PHP File Rendering
    8Monitor
  • CVE-2026-457530 days apartSymfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)
    8Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
P
Scope
X

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records