CVE-2026-66882

LOWPre-NVD 2.12.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This low-severity CVE scores 2.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (53rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
2.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 2.1Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.

When a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain <%= %> expressions, which perform no escaping, so the parameter is reflected verbatim.

Neither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.

The injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.

This issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.

CVSS v3
2.1
EG Score
2.1LOWmedium confidence
EG Risk
25
EG Risk 25/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity21% × 45%
The EG Score, 2.1 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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 available. Apply it within your standard update timelines.
EPSS PROB
0.8%
EPSS %ILE
53rd
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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

August 25, 2026

Last Modified

September 1, 2026

References (5)

Affected Packages

(1 across 1 ecosystem)
Hex(1)
PackageVulnerable rangeFix by version rangeDependents
ash_authentication4.10.0 ... 5.0.0-rc.9 (43 versions)
  • 4.8.0 up to 4.14.2: fixed in 4.14.2
  • 5.0.0-rc.0 up to 5.0.0-rc.13: fixed in 5.0.0-rc.13
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 35× 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. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  4. 2026-10-12 15:46 UTCEG score recompute
  5. 2026-10-11 19:31 UTCEG score recompute
  6. 2026-10-11 16:46 UTCEG score recompute
  7. 2026-10-11 14:07 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  10. 2026-10-10 12:21 UTCEG score recompute
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  12. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  14. 2026-10-07 07:19 UTCEG score recompute
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  18. 2026-10-04 02:15 UTCEG score recompute
  19. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  20. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  21. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  22. 2026-09-30 20:47 UTCEG score recompute
  23. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  24. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  25. 2026-09-27 15:45 UTCEG score recompute
Show 37 more
  1. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  2. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  3. 2026-09-24 10:41 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  5. 2026-09-21 05:37 UTCEG score recompute
  6. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-09-18 00:05 UTCEG score recompute
  9. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-09-14 18:59 UTCEG score recompute
  12. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-09-11 12:57 UTCEG score recompute
  14. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  16. 2026-09-08 07:28 UTCEG score recompute
  17. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  18. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  19. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  20. 2026-09-05 02:26 UTCEG score recompute
  21. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  23. 2026-09-01 21:23 UTCEG score recompute
  24. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-09-01 06:30 UTCEG score recompute
  26. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  27. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  28. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  29. 2026-08-29 01:27 UTCEG score recompute
  30. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  31. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  32. 2026-08-25 20:24 UTCEG score recompute
  33. 2026-08-25 20:01 UTCEG score recompute
  34. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  35. 2026-08-25 08:23 UTCEG score recompute
  36. 2026-08-25 08:15 UTCEG score recomputeFirst assessed: 2.1 LOW
  37. 2026-08-25 08:11 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-66882?
CVE-2026-66882 is a low-severity vulnerability; its CVE record was published on August 25, 2026. Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms. When a strategy is configured with requireinteraction? set to true, AshAuthentication serves…
When was the CVE record for CVE-2026-66882 published?
The CVE record for CVE-2026-66882 was published on August 25, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 1, 2026; the record at its source may have been updated since.
Is CVE-2026-66882 actively exploited?
CVE-2026-66882 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66882?
CVE-2026-66882 has a CVSS base score of 2.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66882?
A fix for CVE-2026-66882 is available: update to the fixed version the vendor names in its advisory.

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