Unpoly is a JavaScript framework for server-side web applications. There is a possible Denial of Service (DoS) vulnerability in the unpoly-rails gem that implements the Unpoly server protocol for Rails applications. This issues affects Rails applications that operate as an upstream of a load balancer's that uses passive health checks. The unpoly-rails gem echoes the request URL as an X-Up-Location response header. By making a request with exceedingly long URLs (paths or query string), an attacker can cause unpoly-rails to write a exceedingly large response header. If the response header is too large to be parsed by a load balancer downstream of the Rails application, it may cause the load balancer to remove the upstream from a load balancing group. This causes that application instance to become unavailable until a configured timeout is reached or until an active healthcheck succeeds. This issue has been fixed and released as version 2.7.2.2 which is available via RubyGems and GitHub. Users unable to upgrade may: Configure your load balancer to use active health checks, e.g. by periodically requesting a route with a known response that indicates healthiness; Configure your load balancer so the maximum size of response headers is at least twice the maximum size of a URL; or instead of changing your server configuration you may also configure your Rails application to delete redundant X-Up-Location headers set by unpoly-rails.
CVE-2023-28846
“—” beside the score: it is equal to NVD's CVSS score.
This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 1.0% (63rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.9
- EG Score
- 5.9MEDIUMmedium confidence
- EG Risk
- 27EG Risk 27/100
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)Severity59% × 45%Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation1.0% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (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
- 1.0%
- EPSS %ILE
- 63rd
- 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 (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 1.0% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
- 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.Each input and its source: 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 available. Apply it within your standard update timelines.
Exploitation none (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
March 30, 2023
Last Modified
November 21, 2024
References (7)
- security-advisories@github · CVE Programhttps://docs.nginx.com/nginx/admin-guide/load-balancer/http-health-check/#passive-health-checksTechnical Description
- security-advisories@github · CVE Programhttps://github.com/unpoly/unpoly-rails/Product
- security-advisories@github · CVE Programhttps://github.com/unpoly/unpoly-rails/commit/cd9ad0007daceeb3b2354fdcab4f88350427bf16Patch · Vendor Advisory
- security-advisories@github · CVE Programhttps://github.com/unpoly/unpoly-rails/security/advisories/GHSA-m875-3xf6-mf78Vendor Advisory
- security-advisories@github · CVE Programhttps://makandracards.com/operations/537537-nginx-proxy-buffer-tuningThird Party Advisory
- security-advisories@github · CVE Programhttps://tryhexadecimal.com/guides/http/414-request-uri-too-longThird Party Advisory
- security-advisories@github · CVE Programhttps://unpoly.com/up.protocolProduct
Affected Packages
(1 across 1 ecosystem)
RubyGems(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| unpoly-rails | 0.20.0 ... 2.7.2.1 (101 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× 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.
Showing the most recent 92 of 195 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 8 repeat rows among the latest 100 are merged into the row they repeat. The 103 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-21 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-20 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-19 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-18 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-18 08:06 UTCEG score recompute
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-16 16:35 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-15 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-14 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
- 2026-10-14 14:54 UTCOSV refresh
- 2026-10-13 16:29 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-12 18:29 UTCEG score recompute
- 2026-10-12 16:30 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-11 21:55 UTCEG score recompute
- 2026-10-11 13:45 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
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- 2026-10-02 16:23 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-01 19:47 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
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- 2026-09-30 16:21 UTCEG score recompute
- 2026-09-30 15:01 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-29 15:16 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-28 13:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-27 13:42 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-26 00:22 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-24 14:01 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-23 16:34 UTCOSV refresh
- 2026-09-23 13:45 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-22 14:45 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-20 20:14 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-16 14:05 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-13 16:44 UTCEPSS rescoreEPSS 1.0% · 61st percentile
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- 2026-09-11 14:50 UTCEPSS rescoreEPSS 1.0% · 61st percentile
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- 2026-09-04 13:58 UTCEPSS rescoreEPSS 1.0% · 61st percentile
- 2026-09-04 11:16 UTCOSV refresh
- 2026-09-04 05:04 UTCEPSS rescoreEPSS 1.0% · 61st percentile
- 2026-09-02 14:09 UTCEPSS rescoreEPSS 1.0% · 61st percentile
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- 2026-08-19 17:02 UTCEPSS rescoreEPSS 1.0% · 61st percentile
- 2026-08-18 13:46 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-17 21:59 UTCOSV refresh
- 2026-08-17 13:44 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-16 14:53 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-16 02:12 UTCEPSS rescoreEPSS 1.0% · 60th percentile
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- 2026-08-13 21:58 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-12 13:48 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-11 13:39 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-08-09 13:44 UTCEPSS rescoreEPSS 1.0% · 60th percentile
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- 2026-08-02 17:27 UTCOSV refresh
- 2026-08-02 02:24 UTCEPSS rescoreEPSS 1.0% · 60th percentile
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- 2026-07-30 16:26 UTCEPSS rescoreEPSS 1.0% · 60th percentile
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- 2026-07-23 14:16 UTCEPSS rescoreEPSS 1.0% · 60th percentile
- 2026-07-23 02:21 UTCEG score recompute
- 2026-07-22 23:09 UTCEG score recompute
- 2026-07-22 14:06 UTCEPSS rescoreEPSS 1.0% · 60th percentile
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Frequently asked(5)
What is CVE-2023-28846?
When was the CVE record for CVE-2023-28846 published?
Is CVE-2023-28846 actively exploited?
What is the CVSS score of CVE-2023-28846?
How do I remediate CVE-2023-28846?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2023-28846
Is Your Infrastructure Affected by CVE-2023-28846?
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