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CVE.org (no NVD analysis yet)· CNA curl

CVE-2026-87863: HSTS response erases persisted entries

Noroxi assessment

Priority: Monitor (action score 32/100)

  • 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: 0.82% (FIRST EPSS); higher than 57.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: azl3 curl 8.11.1-11 on Azure Linux 3.0 Release Notes; azl3 curl 8.11.1-12 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to azl3 curl 8.11.1-11 on Azure Linux 3.0 Release Notes; azl3 curl 8.11.1-12 on Azure Linux 3.0 Release Notes 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

An authenticated HTTPS origin can supply an HSTS `max-age` value that the parser accepts, but time serialization later fails to process. On 64-bit systems, extreme max-age values compute an absolute expiry within standard time integer limits that exceeds calendar time structure bounds. During cache saves, the original HSTS file is truncated before writing a temporary replacement; when serialization fails, the temporary file is deleted, leaving an empty or partial cache. Because the save error is silently ignored during cleanup, curl exits successfully despite the data loss.

HighCVSS 8.1 · v3.1—No exploit Fix available
Published
Oct 20, 2026
Updated
Oct 30, 2026
EPSS
0.8% · 57th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

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.

Follow CVE-2026-87863

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.

—

Versions reported by the vendor

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

  • curl curl

    • 8.22.0 and later · up to and including 8.22.0affected · semver
    • 8.21.0 and later · up to and including 8.21.0affected · semver
    • 8.20.0 and later · up to and including 8.20.0affected · semver
    • 8.19.0 and later · up to and including 8.19.0affected · semver
    • 8.18.0 and later · up to and including 8.18.0affected · semver
    • 8.17.0 and later · up to and including 8.17.0affected · semver
    • 8.16.0 and later · up to and including 8.16.0affected · semver
    • 8.15.0 and later · up to and including 8.15.0affected · semver
    • 8.14.1 and later · up to and including 8.14.1affected · semver
    • 8.14.0 and later · up to and including 8.14.0affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Alpine:v3.23curlbefore 8.23.0-r08.23.0-r0
Debian:13curlfrom 0—
openSUSE:Tumbleweedcurlbefore 8.23.0-1.18.23.0-1.1
Red Hat:hummingbird:1curlbefore 0:8.23.0-0.1.hum10:8.23.0-0.1.hum1
Red Hat:hummingbird:1libcurlbefore 0:8.23.0-0.1.hum10:8.23.0-0.1.hum1
Red Hat:hummingbird:1libcurl-develbefore 0:8.23.0-0.1.hum10:8.23.0-0.1.hum1
Red Hat:hummingbird:1libcurl-minimalbefore 0:8.23.0-0.1.hum10:8.23.0-0.1.hum1
SUSE:Linux Enterprise Installer Updates 15 SP4curlbefore 8.14.1-150400.5.98.18.14.1-150400.5.98.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7curlbefore 8.22.0-150700.7.33.18.22.0-150700.7.33.1
SUSE:Linux Enterprise Server 15 SP6-LTSScurlbefore 8.22.0-150600.4.58.18.22.0-150600.4.58.1

Same product

curl: all records

Other highest-scoring records for the same primary product.

Published before and after this one in the same product

  • ← EarlierCVE-2026-87861Oct 20, 2026 · cross-origin reuse of a Negotiate connection
    36Monitor
  • ← EarlierCVE-2026-87862Oct 20, 2026 · HSTS cache import drops longer-lived child
    32Monitor
  • Later →CVE-2026-87864Oct 20, 2026 · IMAP APPEND plus CRLF conversion command injection
    32Monitor

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
azl3 curl 8.11.1-11 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 curl 8.11.1-12 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
alpine:curl8.23.0-r0 · Alpine:v3.23Package registry (OSV)
opensuse:curl8.23.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:curl0:8.23.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl0:8.23.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl-devel0:8.23.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl-minimal0:8.23.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:curl8.14.1-150400.5.98.1 · SUSE:Linux Enterprise Installer Updates 15 SP4Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 10, 2026+21 d
EPSS, last 120 days+1% in 7 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.

No commit or PR link among the references.

Credits

All researchers

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

Variant candidates

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

  • CVE-2026-864130 days apartNegotiate credentials sent to redirected origin
    36Monitor
  • CVE-2026-864140 days apartleaking host credentials to HTTP proxy
    36Monitor
  • CVE-2026-878610 days apartcross-origin reuse of a Negotiate connection
    36Monitor
  • CVE-2026-864090 days apartstale SigV4 headers sent unintended
    32Monitor
  • CVE-2026-878620 days apartHSTS cache import drops longer-lived child
    32Monitor
  • CVE-2026-864150 days apartauto client cert connection reuse mixup
    30Monitor

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

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-201 · Insertion of Sensitive Information Into Sent Data

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

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. CVSS— → 8.1
  2. Severity— → high
  3. SSVC exploitation— → poc
  4. Fix✗ → ✓
  5. Exploit maturity— → none

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

References

Show all references (2 more)

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

All records