Weak signing secret in CallBackery lets attackers forge session cookies
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
CallBackery versions before 0.62.0 for Perl generate the secret that signs session cookies from two calls to the built-in rand(), which is seeded with only 32 bits. This gives the secret at most 2**32 possible values, and a single signed cookie lets an attacker test each candidate offline (CWE-338). An attacker who obtains one session cookie can recover the secret and sign cookies for any user, including an administrator, over the network without authentication.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
CallBackery versions before 0.62.0 for Perl allow session cookie forgery via a signing secret generated with rand(). The secret that signs session cookies is built from two calls to the built-in rand(), which is seeded with 32 bits. The secret therefore has at most 2**32 possible values, and one signed cookie is enough to test each candidate offline. An attacker who obtains a single session cookie can recover the secret and sign cookies for any user, including an administrator.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | CallBackery | before 0.62.0 | 0.62.0 | Patch available | CNA |
- CallBackery Vendor— Affected before 0.62.0 Fixed in 0.62.0 Patch available CNA
Remediation
CallBackery users should upgrade to version 0.62.0.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA CallBackery Fixed in 0.62.0
Timeline
- 2026-10-30 Threatist record created from CVE-2026-118986
- 2026-10-30 Alias added: GHSA-fr5m-676f-94fg
- 2026-11-06 CVSS score added · CISA ADP
- 2026-11-06 CISA SSVC decision points changed
References
Sources
- CVE-2026-118986 · CVE Program
- CVE-2026-118986 · NVD
- FIRST EPSS
- GHSA-fr5m-676f-94fg · GitHub Advisory Database · CC BY 4.0
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