vciy

CVE-2021-42697

INDEX BUILT · 2026-09-20

No source can show you its own past. This one can.

Print this page to keep the view as it stands on this date. Everything hidden behind a disclosure opens, and every receipt prints with its value.

Akka HTTP 10.1.x before 10.1.15 and 10.2.x before 10.2.7 can encounter stack exhaustion while parsing HTTP headers, which allows a remote attacker to…

CVE-2021-426973 of 4 sources documented this
43

rank 43 = 20 + 19 + 0 + 4 + 0

rank@v1 · scheduled

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.36139  ·  without this subject the record ranks 23

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 7.5, from NVD  ·  without this subject the record ranks 24

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 43

How much of the world it touches

NVD CPE configurations

2 products in the CPE ranges  ·  without this subject the record ranks 39

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 43

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$1.10Mover the next 30 days, if this record is yours
Movement+$519,000on 2024-12-17, the last material move, 1 year, 5 months before this reading
Basisassumeda published average, not your estate

$1.10M = $4.99M incident cost x 0.6121449559255632 exposure x 0.36139 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.36139EPSSNOT IN KEVas of 2026-09-20
Severity7.5 HIGHreceipt
Harmunauthenticated · networkreceipt
Exploitationpublic proof-of-conceptreceipt
Defenseunaffected versions publishedreceipt
Movementthreshold crossedreceipt
RISING10Risen from 0.013 to 0.36139 across 63 observations. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

Check a version against this record

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

Watch this record

Matches your own product list against every record this index holds, and tells you when one of them moves.

What counts as a move

Set up a watchlist (needs a Practitioner account)

Record your call

Keep your verdict, your reason and the evidence together. The record takes its date when you save it.

AcceptDeferPatch by…Not affectedMitigated

Choose your verdict, then sign in or use an email link. Your first 100 records are free. Evidence is frozen when the record is created.

Private to your organization unless you share it. Put the proof link in your ticket so a reviewer can inspect the basis for your call. See how decision records work.

Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachnetwork-reachable · no privileges required · no user interaction · low attack complexityreceipt
ImpactComplete availability lossreceipt
Scored fromCVSS v3.1 · NVD's vectorreceipt
Weakness classCWE-674 Uncontrolled Recursionreceipt
Published consequencesCWE-674: Availability: DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory); Confidentiality: Read Application Data[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

First unaffected version, by branchhttp server 10.1.15; http server 10.2.7receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Proof-of-concept published · 1 public repository, 2022-04-24.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published · 1 public repository2022-04-24receipt
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, NVD7.5 HIGHreceipt
Exploit probability0.36139 · top 2% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned bymitrereceipt
Recorded changes66 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Named in the CPE rangesAkka http serverreceipt
Published rangesakka http server >= 10.1.0 < 10.1.15; akka http server >= 10.2.0 < 10.2.7receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

Did this affect your environment?Answering needs an account.

What it is stated by the CNA

Akka HTTP 10.1.x before 10.1.15 and 10.2.x before 10.2.7 can encounter stack exhaustion while parsing HTTP headers, which allows a remote attacker to conduct a Denial of Service attack by sending a User-Agent header with deeply nested comments. receipt

NVD's analysis a second authority

severity
7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
weakness
CWE-674
affected versions
akka http server >= 10.1.0 < 10.1.15; akka http server >= 10.2.0 < 10.2.7

check it yourself akka.io doc.akka.io akka.io akka.io packetstormsecurity.com receipt

Dated events

2022-05-12EPSS moved 0.01 to 0.092025-03-17EPSS moved 0.20 to 0.642026-06-15EPSS moved 0.76 to 0.36

Movement the material steps

3 Nov 20210.013
27 Jun 20220.18528 · crossed 0.10
15 Jul 20220.07176 · crossed 0.10
15 Nov 20220.18528 · crossed 0.10
7 Mar 20230.00995 · crossed 0.10 · scoring model v2023.03.01
17 Dec 20240.26021 · crossed 0.10
17 Mar 20250.64237 · crossed 0.50 · scoring model v2025.03.14
29 Mar 20250.75267
1 May 20250.62622
12 May 20250.80195
18 Nov 20250.59434
21 Nov 20250.75541
15 Jun 20260.36139 · crossed 0.50 · scoring model v2026.06.15
Show all 63 observations
3 Nov 20210.013
6 Jan 20220.05581
4 Feb 20220.05736
1 Apr 20220.01136
16 Apr 20220.01213
12 May 20220.08944
27 Jun 20220.18528
15 Jul 20220.07176
15 Nov 20220.18528
7 Mar 20230.00995
15 Apr 20230.01194
13 May 20230.01452
26 May 20230.01635
10 Jun 20230.01639
24 Jun 20230.01954
22 Aug 20230.02120
8 Jun 20240.02553
22 Jun 20240.03149
18 Jul 20240.03971
1 Aug 20240.05271
28 Aug 20240.06583
5 Dec 20240.09028
17 Dec 20240.26021
3 Jan 20250.22206
18 Feb 20250.19771
17 Mar 20250.64237
19 Mar 20250.68015
20 Mar 20250.64237
23 Mar 20250.71563
24 Mar 20250.68145
27 Mar 20250.71563
28 Mar 20250.68145
29 Mar 20250.75267
30 Mar 20250.68145
11 Apr 20250.701
1 May 20250.62622
4 May 20250.701
12 May 20250.80195
1 Jun 20250.73698
4 Jun 20250.78648
14 Jun 20250.76376
25 Jun 20250.75541
1 Jul 20250.7501
4 Jul 20250.75541
1 Aug 20250.7501
4 Aug 20250.75541
1 Sep 20250.7501
4 Sep 20250.75541
1 Oct 20250.7501
4 Oct 20250.75541
1 Nov 20250.7501
4 Nov 20250.75541
18 Nov 20250.59434
21 Nov 20250.75541
1 Dec 20250.7501
4 Dec 20250.75541
1 Jan 20260.7501
4 Jan 20260.75541
1 Feb 20260.7501
4 Feb 20260.75541
1 Mar 20260.7501
4 Mar 20260.75541
15 Jun 20260.36139

63 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.36139Published2021-11-02Public PoC2022-04-24Index as of2026-06-15

The record had been public for 4 years, 7 months when this index was last written.

Published 2021-11-02 receipt · Public PoC 2022-04-24 receipt · Index as of 2026-06-15 derived

Siblings and hubs

Records related to this one

Browse the index from here

These are index-wide views, not findings about CVE-2021-42697.

What usually comes next

Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.

Everything on this page is free. Public data. Withholding it protects nothing.