In RubyGem excon, interrupted Persistent Connections May Leak Response Data
In RubyGem excon before 0.71.0, there was a race condition around persistent connections, where a connection which is interrupted (such as by a timeout) would leave data on the socket. Subsequent requests would then read this data, returning content from the previous response. The race condition window appears to be short, and it would be difficult to purposefully exploit this.
- Published
- Dec 16, 2019
- Updated
- Jul 28, 2026
- EPSS
- 1.7% · 76th percentile
- CWE
- CWE-664
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.7%
CNA vs NVD score
- NVD
- 5.9
- CNA · GitHub_M
- 5.8
- 0.1 point gap
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| excon project | excon | cpe:2.3:a:excon_project:excon |
| opensuse | backports sle | cpe:2.3:a:opensuse:backports_sle |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux8.0
- excon project exconbefore 0.71.0
- opensuse backports sle15.0
- opensuse leap15.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
excon excon
- < 0.71.0 and later · before 0.71.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | ruby-excon | before 0.60.0-2 | 0.60.0-2 |
| Debian:8 | ruby-excon | before 0.33.0-2+deb8u1 | 0.33.0-2+deb8u1 |
| openSUSE:Leap 15.1 | rubygem-excon | before 0.59.0-lp151.3.3.1 | 0.59.0-lp151.3.3.1 |
| RubyGems | excon | before 0.71.0 | 0.71.0 |
| SUSE:Linux Enterprise Module for Containers 12 | rubygem-excon | before 0.52.0-12.3.8 | 0.52.0-12.3.8 |
| SUSE:Package Hub 15 SP1 | rubygem-excon | before 0.59.0-bp151.4.3.1 | 0.59.0-bp151.4.3.1 |
Same product
excon project: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-54171Excon: redact additional sensitive/risky headers when following redirects26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:ruby-excon | 0.60.0-2 · Debian:12 | Package registry (OSV) |
| opensuse:rubygem-excon | 0.59.0-lp151.3.3.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| RubyGems:excon | 0.71.0 | Package registry (OSV) |
| suse:rubygem-excon | 0.52.0-12.3.8 · SUSE:Linux Enterprise Module for Containers 12 | Package 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.
No dated events beyond publication.
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.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
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
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
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
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-664 · Improper Control of a Resource Through its LifetimeCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Session Credential Falsification through ForgingCAPEC-196likelihood: Medium · Medium
- Exploitation of Trusted IdentifiersCAPEC-21likelihood: High · High
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
- Session FixationCAPEC-61likelihood: Medium · High
- Cross Site Request ForgeryCAPEC-62likelihood: High · Very High
ATT&CK techniques
- Access Token ManipulationT1134
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Access Token Manipulation: Create Process with TokenT1134.002
- Access Token Manipulation: Make and Impersonate TokenT1134.003
- Steal Application Access TokenT1528
- Steal Web Session CookieT1539
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Forge Web CredentialsT1606
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2020-01/msg00021.html
- lists.opensuse.org/opensuse-security-announce/2020-01/msg00062.html
- github.com/excon/excon/commit/ccb57d7a422f020dc74f1de4e8fb505ab46d8a29
- github.com/excon/excon/security/advisories/GHSA-q58g-455p-8vw9
- lists.debian.org/debian-lts-announce/2020/01/msg00015.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.