CVE-2026-121949

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 5.4 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from CISA-ADP (Vulnrichment) CVSS v3.1
Sources: CISA-ADP (Vulnrichment) CVSS v3.1
Trending — 4 sources updated this week

Also known asEUVD-2026-117624 (ENISA EUVD)Source: ENISA EUVD

5.4EG
EchelonGraph verdictMonitorNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

The Symfony HtmlSanitizer component does not apply the media URL policy to the srcset and imagesrcset attributes, allowing values that point to hosts or schemes not permitted by allowMediaSchemes() or allowMediaHosts() to bypass it, so that browsers load images from disallowed hosts in Symfony versions 6.1.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.The srcset attribute on img and source elements and the imagesrcset attribute on link elements are allowed by the sanitizer, but their URL candidates are never validated, so their values are kept verbatim while the same URL in src is dropped. The fixes for CVE-2026-45753 and CVE-2026-48761 extended the same attribute list but did not cover these two attributes. For example, with allowMediaSchemes(['https']) and allowMediaHosts(['trusted.example']), survives sanitization, and the browser fetches the selected candidate as it would fetch src. Candidates with a scheme forbidden by the configuration, such as http, are kept as well. Any application that sanitizes untrusted HTML and relies on the media schemes and hosts allowlists to restrict where images can be loaded from is affected. A single crafted value is enough to make the browser of a user viewing the sanitized content send a request to an attacker-controlled host, which can be used to track viewers or log their IP addresses. No authentication is needed if the application accepts HTML from unauthenticated users.

CVSS v3
5.4
EG Score
5.4MEDIUMlow confidence
EG Risk
24
EG Risk 24/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity54% × 45%
Impact severity (EG Severity): CVSS 5.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0% × 40%
No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.4): severity, escalated by confirmed exploitation. This CVE's 5.4 is its impact severity (EG Severity), not escalated.

EG Severity
5.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.CISA-ADP (Vulnrichment) CVSS v3.1 · CVSS v3.1
EG Likelihood
Unknown (no EPSS on record)Unknown, not low: FIRST has published no EPSS probability for this CVE.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

November 5, 2026

Last Modified

November 5, 2026

References (2)

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 6× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-05 20:29 UTCEG score recompute▲ 3.10
  2. 2026-11-05 20:26 UTCNVD updateCVSS v3 → 5.4 · severity → MEDIUM
  3. 2026-11-05 19:04 UTCENISA EUVD ID recordedEUVD-2026-117624 · Source: ENISA EUVD
  4. 2026-11-05 18:27 UTCEG score recompute
  5. 2026-11-05 17:54 UTCEG score recomputeFirst assessed: 2.3 LOW
  6. 2026-11-05 17:53 UTCMITRE cvelistV5first tracked

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Frequently asked(4)

What is CVE-2026-121949?
CVE-2026-121949 is a medium-severity vulnerability; its CVE record was published on November 5, 2026. The Symfony HtmlSanitizer component does not apply the media URL policy to the srcset and imagesrcset attributes, allowing values that point to hosts or schemes not permitted by allowMediaSchemes() or allowMediaHosts() to bypass it, so that browsers load images from disallowed hosts in Symfony…
When was CVE-2026-121949 made public?
CVE-2026-121949 was made public on November 5, 2026: that is the date its CVE record's CNA, Checkmarx, gives for when the vulnerability was made public. The CVE record itself was published on November 5, 2026. EchelonGraph's copy of the record carries a last-modified date of November 5, 2026; the record at its source may have been updated since.
What is the CVSS score of CVE-2026-121949?
CVE-2026-121949 has a CVSS v3.1 base score of 5.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-121949?
A fix for CVE-2026-121949 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

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